The response time isn't really something to worry about.

Some people are uptight about it - but that's totally an indication of their personality. If they want instant replies (ok I'm thinking of texting right now) then we'll, it could indicate a lot of neediness or jealousy. If they get annoyed with quick replies then they're probably rather judgemental.

Or not! Everyone is different. And everyone has different schedules and habits. 😀 Plus if you get a message and reply right after it's been sent, then you're both online and could end up as a back and forth conversation!