The average date for the NT writers is 50 - 65 ad however.
Except for Paul, that is not at all my understanding. So, for example ...
MARK
Most scholars date Mark to c. 66–74 AD, either shortly before or after the destruction of the
Second Temple in 70 AD.
[6] They reject the traditional ascription to
Mark the Evangelist, the companion of the
Apostle Peter, which probably arose from the desire of early Christians to link the work to an authoritative figure, and believe it to be the work of an author working with various sources including collections of miracle stories, controversy stories, parables, and a passion narrative.
[7] It was traditionally placed second, and sometimes fourth, in the Christian canon, as an inferior abridgement of what was regarded as the most important gospel,
Matthew.
[8] The Church has consequently derived its view of Jesus primarily from Matthew, secondarily from
John, and only distantly from Mark.
MATTHEW
Most scholars believe the gospel was composed between AD 80 and 90, with a range of possibility between AD 70 to 110; a pre-70 date remains a minority view.
[9][10] The work does not identify its author, and the early tradition attributing it to the apostle
Matthew is rejected by modern scholars.
[11][12] He was probably a male
Jew, standing on the margin between traditional and non-traditional Jewish values, and familiar with technical legal aspects of scripture being debated in his time.
[13] Writing in a polished Semitic "synagogue Greek", he drew on the
Gospel of Mark as a source, plus the hypothetical collection of sayings known as the
Q source (material shared with Luke but not with Mark) and material unique to his own community, called the
M source or "Special Matthew".
[14][15]
LUKE
The author is anonymous;
[6] the traditional view that it was
Luke the Evangelist, the companion of Paul, is still occasionally put forward, but the scholarly consensus emphasises the many contradictions between Acts and the authentic Pauline letters.
[7][8] The most probable date for its composition is around AD 80–110, and there is evidence that it was still being revised well into the 2nd century.
[9]
JOHN
John reached its final form around AD 90–110,
[5] although it contains signs of origins dating back to AD 70 and possibly even earlier.
[6] Like the three other gospels, it is anonymous, although it identifies an unnamed "
disciple whom Jesus loved" as the source of its traditions.
[7][8] It most likely arose within a "
Johannine community",
[9][10] and as it is closely related in style and content to the three
Johannine epistles most scholars treat the four books, along with the
Book of Revelation, as a single corpus of
Johannine literature, albeit not from the same author.
[11]
See, also,
Early Christian Writings.