You have NO IDEA how much I relate to this right here. I got my phone when I was in 8TH GRADE!! It took my parents sooooo long to finally gimme one. That meant I could contact no one at all. And yes, I liked a guy that I couldn't contact, pretty sure he liked me back. Backstory Time!!!: We hung out, our relationship got ruined and he wouldn't talk to me. I am introverted, so I didn't either. This year, my friend gave me his number and I texted him. He hates me and ignores me and I don't even know why...
Anyways... So the way I did (this is really sad and cringey) was use my mom's phone and got people's phone numbers to put in there. But since you can have your phone period, I would just ask to exchange on a piece of paper or you put you number in his phone so he could text you first. I also have very strict parents so maybe tell him that you want to talk more, but your parents don't let you have your phone out during the week. Then that can sound like he knows you're not ignoring his texts and you really wanna talk to him. Hope this helps!
-Corn