Do i have a mental disease?

So I am 16 and my sister is 13. I have never had a boyfriend, never kissed anyone, nothing. I am horrible with guys. She has already had one boyfriend and although it was a middle school bf that only lasted for a a couple weeks i’m still jealous. She also has much more friends than me and facetimes them multiple times a week. I listen into what she talks about because I want to know if she gets another boyfriend. She isn’t supposed to date until highschool and i’m just so paranoid that she’ll do something without me knowing. I actually think I am going insane why can’t I just have trust in her and be happy for her. I’m very insecure obviously. Thoughts?