I’m lonely

I’m 18 and lonely. I want a relationship but always get scared and turn down other guys that want to get together. I’ve never had an actual boyfriend, I’ve talked to some guys but never dated. I’ve never had my first kiss, never held a guys hand, and never been on a date...IM 18!!!! My younger sister, my twin brother and my mom are all in a relationship this year. And I’m always stuck at home when they go on dates. And I just feel unwanted. Yet people tell me I’m the nicest person and so goofy, am I too nice and sensitive!? Most my friends are guys and I’m just a younger sister to them, is that why nobody wants me? People think I’m gay because I hangout with guys! My girl friends are older and in college and I was still in high school :( People compare me to my younger sister and say “she’s prettier than you” “you’re fatter than her”... I used to cry every night for as long as I can remember, and now I can’t even cry. I haven’t been able to cry for like 4 months now. Idk if that’s a good thing, I don’t feel sad or happy, I just feel nothing. I just wrote all this to get it out of my system because I hate telling the people in my life how I feel.I get embarrassed. So if you read it to the end, thank you <3