Try but always negative

Kaitlyn
Okay so I'm 21 boyfriend is 26. We have been TTC for 3 months or so.. I need advice as to why it hasn't happened yet. I thought for sure last month I was, my period was a week late and then I took a test and nothing. It's upsetting! I don't understand why it hasnt happened yet because we should both be at peak fertility rates!?
HELP!!