The new witch, Gloria said that she could control her aging and won't age. So it means that she's immortal, right? But does it do the same with Bonnie?

no actually she said that she could control her aging, so she would age slower, but she definitely ages. This means she is not immortal, but just aging slower than normal. It depends if Bonnie will age slower too. If she can control it, maybe she will do that too...

Not immortal... just aging slower. But she said that one day it would catch up to her. She might live longer, but not forever.