Welcome Valentyne,
I did the very same thing as you, only, I didn't discover all the wonderful help that exists here until further on in my tutorial. I feel it's best to raze your buildings a little at a time if there is a large number that you wish to relocate. This will give you time to build on resources between the moves. If you've only a handful to raze, I would suggest doing it now before you upgrade any of them.
Feel free to add me as a friend if you'd like. Even though I'm still a newbie, I'll help you as much as I'm able to.