The idea that the disciples of Jesus didn’t have good record keeping abilities or skills, due to having no education could well have been gleaned from their encounter with the Sanhedrin in Jerusalem while they were proclaiming Jesus’s resurrection.
A passage that comes to mind is Act 4:13:
When [the religious leaders] saw the courage of Peter and John and realized that they were unschooled, ordinary men, they were astonished”.
It’s for this reason lots of skeptics likely took issues with the idea that Jesus’s disciples could’ve written the gospels (with the exception of Lukan gospel record) or the epistles attributed to them. How would “uneducated’ and “unlearned’ men have written such records, one which is next to masterpieces, they say.
But, the word “agrammatoi’ as used in the text have limited usage in the context. For instance, “grammata’ was used in John 7:15 for letters, which though Jesus wasn’t learned in, yet was able to so eloquently and coherently handle. The passage spake nothing of course about education of having basic oral grasp of “the law and the prophets’ or been able to record, write or even read(been/being prerequisite for basic literacy). The disciples of Jesus were thought of as been illiterate in the sense of their limited religious knowledge and handling/interpreting of the Jewish text. It’d be an exaggeration to think they were after all stack illiterate given the status of some of the disciples.
There are very important points to consider in the light of the critics objections to the record keeping abilities of the disciples of Jesus, and it’ll be good to highlight them here:
1) The disciples of Jesus actually cut across a wide Jewish geographic landscape. Jesus’s had disciples from across first century Israel:
Luke 6:13 [Jesus] called his disciples to him and chose twelve of them whom he also designated apostles.
Luke 6:17 He went down with them [the 12 apostles] and stood on a level place. A large crowd of his disciples was there and a great number of people from all over….
Luke 10:1 …the Lord appointed seventy-two and sent them two by two ahead of him…
Luke 19:37 When he came near the place where the road goes down from the Mount of Olives, the whole crowd of disciples began joyfully to praise God…
Essentially his ministry expanded their number beyond 12. There were people like Joanna (the wife of Chuza, the manager of Herod’s household) who wouldn’t have been without education in Greek, Latin, and probably aramaic, Joseph of Arimatea, Matthew a tax collector, who was probably fluent in the languages spoken in his area (Greek, Latin, Aramaic). We can very well say that Jesus’s disciples weren’t without close people who could’ve taken dictation of the letters IF we are to concede that the main disciples were unlettered. And apparently, there are epistles that evidence point at as been a product of dictation.
2) The ordinary and uneducated nature of the disciples was grossly exaggerated:
The New Testament scholar M. Wilkins believes that “James and John” were from a family of some wealth and influence, based on the information we have about their fishing business (cf. Mk 1:19). Peter ran a fishing business with his brother Andrew and their partners, James and John (Mk 1:16-20; Luke 5:10)  He seemed also to have owned a house with his brother Andrew (Mk 1:29). Mark’s text suggest that the house was not far from the synagogue in Capernaum (compare Mk 1:21 with 1:29). Perhaps, Peter, James and John probably knew Greek well enough given the nature of their works.
On this, Carsten Thiede comments, “an active knowledge of Greek would have been obligatory for people like Peter and his co-workers, Andrew, James and John (Mk 1:16; Lk 5:10), who were involved in the fishing industry and trade’. Of course, such Knowledge could’ve been elementary. And the Hellenistic elements of their surrounding is obvious in their names (Petros-Rock, Yehanan: Grace, and James: supplant).
From the record of the interaction of Philip with the Greek who came to see Jesus in John 12:20-26, Philip, who bore a Greek name, and likely knew Greek, could’ve been interactively involved with Greek pilgrims and the Greek community in Jerusalem. In essence, the disciples of Jesus aren’t as unschooled as many have been made to believe.
3) The conscientiousness with which they record numbers:
Very few people can conscientiously record, and commit numbers to memory for record sake, educated people are more appraised to be able do so, uneducated people are unlikely to do, perhaps, due to lack of regard for statistical figures/data. But the conscientiousness with which the disciples handled rather complex data is considerable. This may not sound intriguing if one haven’t thought through it. The story of the feeding of 4000 men and also 5000 men comes to mind. Matthew 14:19-22 recorded how 5000 men, excluding the women and children, were fed with five loaves and two fishes. Luke 8:1-9 recorded how 4000 men were also fed with seven loaves of bread.
A closer look at the overlap in records of the statement of Jesus stating the different account in Matthew 8:19-20 which stated the performance of both miracles, the number of those fed, the number of baskets remaining shows how conscientious the disciples of Jesus would’ve been in taking records. We must note that the setting of the event look in no way formal, as an average event of our time, yet, there was a specificity with the figures of those presents as also the management of remaining baskets. They likely counted the people and even forecasted how much bread could be enough for their upkeep. That smacks much of conscientiousness than anything else.
Apparently, it’ll be disingenuous to take their testimony for granted for the reason that, they aren’t as much as literate as has been wrongly thought. They in fact aren’t as dumb as many has been made to believe. Most of them may not be of the Sanhedrin lot, but they sure have the basic requisite to recording events.