Please Help me! What would you do? Girls plz?

I just feel so confused! I really want to have with my boyfriend for my first time ever. but the problem is im overweight and have been trying to lose weight , and I feel like birth control can put me losing weight in jeopardy... but i also dont want to get pregnant of course, we planned on using a condom of course but that may not be enough from preventing pregnancy. Should I just hold off on the , this could be months from now.... UGH SO CONFUSED