Returning to OTB after a long time

Hello, I started playing chess at 8 and quit OTB/coaching 12-13. However, despite quitting OTB, I continued to read books and play online daily, reaching 2000+ rapid at 14. I returned now as an older teenager. when i was 11, I was around 1400-1500 USCF and won the championship. Right now, I am 2400+ in chess.com blitz (i began trying harder this summer). I have a few questions:

How well does blitz rating relate to OTB rating?
Is it too late to become an NM, IM, or GM?
What is different in OTB than online? What should I expect?

idk anything but i dont think that its too late to become a gm!

Slay

There are several people who received their GM title in their 80s.

https://khelnow.com/chess/2023-02-chess-top-five-oldest-players-to-become-grandmasters

Cyrus Lakdawala received his IM title well in his 40s.

My advice would be to stop worrying about your age and work on your game instead.