What is the tense of 「卒業して5年になる」?


I was studying the te-form in depth and found out that it can be used as a
starting point ([起点](https://yousei.arc-
academy.net/manbow/index.php/term/detail/857)) and a Japanese friend of mine
told me that it is the same as ～てから; just an omission of から. It seems to be
common to be used as a set phrase like `something + して + time + になる`, like the
exemple sentence in the title, or the one inside the link (`結婚して十年になる`). When
I asked to my friend why なる instead of なった or なっている, they just translated to
"we have been married for 10 years".

Can the "present tense" of Japanese verbs be used the same way as the present
perfect continuous in English? It's not very common to find other information
about the usage of the present tense and present perfect continuous in
Japanese ( _if you know it, even written in Japanese, let me know_ ), only
that it can represent habits or the future tense. It doesn't seem to make
sense to be in the future tense, and habits don't seem to work well here too.
That's why I thought it could be `なっている`.

I [found](https://yousei.arc-academy.net/manbow/index.php/term/detail/418)
that stative verbs like ある and いる (and that also includes なる, probably) can be
used in the present tense to well... indicate a state.

>
> 動詞では状態動詞（「ある」「いる」など）では「今家にいる」「明日は家にいる」のように、現在・未来の両方を表すことができるので「現在・未来形」と呼ばれることもある。

Then, what would be the difference between なる and なっている?

