advice on knowing when to ttc

My fiance has wanted a baby for a while i made him wait were now engaged to be married next year August im 21 in my junior year of college and we have our own place. So many of our friends are starting there lives and look so happy and im so happy with my fiance but i feel im missing this happiness if having a little us thinking i have to wait til im married because i dont wanna walk down the aisle pregnant or wait til im graduated because thats how i was raised. Any advice from ladies who got pregnant before the wedding or graduation or helpful advice in general On wether its smart to just wait, i Over think everything 🙄