Should I be worried?

Yahnee
So I've been talking to this guy for about a month now. I live in California and he lives in Texas. I have known him for about 6 years and we tried dating then but it was something always in the way. So a couple weeks ago he liked a picture on my Instagram and then I messaged him and from then we've been talking. About me moving there and marriage and babies. Well this week he's been extremely distant and out of nowhere said he wanted to take things slow. He doesn't want to rush anything. And I have barely heard from him. Do I just let it go or see if he's just scared? I have no idea what to do!