As a 13 year old myself (Turned 13 about a week ago) it doesn't really feel different. But, happy early birthday!

Honestly, there wasn't much difference between me when I was 12 and me when I was 13, I changed more when I went from 11 to 12 than I did from 12 to 13 or 13 to 14. Aside from the social media things, I don't think you'll notice much difference.

When you're 13 not much really happens. For me, turning 16 was a big difference. Year 11 and 12 in school really screws you up in the head. My advice to you is to live life while it lasts, you have the freedom of doing nothing on weekends, etc. Be prepared for hell in 4 years kiddo.