I have a cavity... I am only in my first trimester.. should I wait until my second? And what should I avoid for anesthetics

You should definitely wait until you are in your second trimester. It is safe for local anaesthetic (freezing) then. If the cavity isn't too bad it would be even better to wait until you deliver your baby.

Good luck.

I had terrible in my last pregnancy 18 years ago and subsequently had my tooth pulled by my dentist the anastethic made me nauseas and gave me palpitations ,my GP recommended a non adrenalin based anastethic next time.when they took the tooth out they discovered there was nothing wrong with it ,it was completely healthy .thats when I learnt that preggy woman can get severe tooth pain and it goes after baby arrives .so keep that in mind.