making friends after high school ?

So I wanted to get some opinions of you ladies. I'm 21, and got engaged and I know that's fairly early to be starting life with someone. I didn't have many friends in high school, I just didn't connect with very many people they where all so clichey and none of them where very nice. I only have about 2 people that I like to hang out with besides my fiancé, and I've known them since middle school. I'm a part time student at a community college and no one really talks at all in the only 2 classes I'm in, everyone at my workplace is atleast 15 years older than me. So what's a good way to make friends out of high school? I know it sounds like a silly question but I've never really had this issue before and I feel like things would be better if I wasn't so lonely:(