Am I overreacting about my bf having female friends?

So I’m 17 and so is my bf and we have been dating for a year now. So back in August when we were 8 months into the relationship my bf found some girl that he was friends with back in middle school. He started talking to her and catching up or whatever so I didn’t care at that point because I trust him. Then he asked her for her number. (I have his Instagram account so I can see his dms). That’s when I got mad. I also know that he was texting her when he was taking almost 3 hours to text me back. I confronted him about it and he hasn’t done that again. But I was reading his dms with his friend and I saw him say “create a clone of me that isn’t me and hit up Diana.” I got so pissed when I saw that because now I know he hands some type of interest in her when he told me he didn’t. He still to this day looks up her Instagram profile and has her Snapchat after I told him to block it. I get jealous really easily so please help!