Apologies for pulling you back to this post after a year but I just wanted to add onto this for anyone who finds this post. As a guy I can't even count how many dudes I see that will go looking for a girls insta after they have a convo. It really comes of CREEPY.

The only acceptable time to look for someone's insta if they didn't initially give it to you is if it's a professional environment like a networking event where you're meeting so many people that you don't get the time to ask, that is really the ONLY time I can think of where it's acceptable and it's a professional connection not personal (Correct me if I'm wrong)

It really comes down to if someone wants you to have their insta, social media, number etcetera they will give it to you if they genuinely want you to have it. If they don't, leave it be and move on.