Recently I've noticed a sudden growth in my body hair. My stomach has got a lot more hairy, particularly the part just below the belly button. I have also noticed a big change in my peach fuzz. It has gotten longer and a bit more noticeable in photos. I don't know whether or not to start shaving it. I'm not sure what is causing these sudden growths and I'm not complaining but I am a bit concerned. I'm not on T yet. Does anybody know what could be causing this?

Wishful thinking and age. I had a happy trail since my 20's. Doc said it was due to excess T from pregnancy. It never left and I never complained.

If you are sure something has changed.. Medically, PCOS is the most likely cause of high T.
Very very rarely, ovarian/adrenal 'nasties' can do it.
Do see a doctor if you are concerned!

Like others said, see a doctor if concerned, it could be something like PCOS, or other issues.

But, like LordKat said, it could also be age. While I know you're not old, as you age your body does change. It's not uncommon AT ALL for females to have thick hair on their bodies in certain areas or even get some facial hair. It's just not widely talked about by women and it's actively hidden, so that's probably why it seems unusual and exciting for you. There's plenty of women even in their 20s and 30s who start getting bits of whiskers on their face who just get it waxed or threaded off, and even buy at-home laser hair removal kits or go to a professional. I used to work in a nursing home, and all the old ladies are quite hairy.  The older you get, the more males and females start looking the same.

Shave it off if you want to, it might be fun for you. It won't hurt anything.