I need boy advice !!

Celeste ✨
This is gonna be long so I apologize in advance. I'm grounded and I don't really have close friends lately (they're all with new people and I'm busy with clubs) so I have nobody to vent to 🙃 anyway. I read this post a while ago that said not to go for the guy that makes you have butterflies but go for the guy that makes you feel calm & relaxed. I saw it on tumblr so it probably doesn't have much weight to it 😂 but is that true?? I'm interested in two people right now. One I've known since freshman year but we only got to know each other more this year (we are seniors). His name is Alex. He's intelligent and kind and has the same sense of humor as I do. He makes me feel comfortable around him and he's super open minded so we talk about anything. The downside is that he's very introverted unless someone talks to him first or unless he's really close with him. While that's totally okay, I'm not like that so it's hard for me to understand when I should talk to him and when I shouldn't. He never makes the first move even though he has a great time whenever we talk or hang out. I have just gotten annoyed with doing it all the time and I don't truly know if he sees me as just a friend or more than a friend. Guy number 2 is named Matt. I met him at the end of the school year and we sorta talked this summer. Right now I see him every morning and we walk to our buses together. Every time I see him or he messages me I get butterflies and I get super nervous and excited but I don't know why because I don't know him much 😂 he understands if I'm quiet or something and he tries his best to make conversation. He's also joining the club I'm leading and he's doing it for me which made me super happy. However! I'm always nervous and that sometimes leads to awkward silences. With everyone else though I'm perfectly fine, witty, energetic, etc. I don't know how to get to know him because I can't figure out how to calm down around him ! And I don't know how to get on the same page Alex is on. I know where I stand with Matt but not with Alex. Should I pursue them both and see where it goes or just one ??