anyone have advice on marrying young?

Engaged at 21- getting married at 22. Everyone is telling me that my life will be over and that I won't get the experience of being in my twenties. I've only ever dated my fiancé and I keep hearing people say that I didn't get to play the field and see what is out there. I was wondering if anyone had advice in general for marrying young. And how you found friends? I feel like we won't be able to find another young couple because all of my friends are single and not looking.