First time having extensions, is this normal?

I’m really worried I am going to cause my hair to thin. It already is thinning a bit where my part is. This is my first time getting extensions. I got them on 2/25, it is 3/31, I am having them moved up 4/8. I feel like this part is lower than at the sides of my head. I do sleep with it in a low pony or braid, and I do put it in a pony or braid for the gym. I think this may be causing tension/slippage in the back but I don’t know if this is something to expect? Also does anyone have any extension friendly hairstyles for the gym so I don’t continue to have this issue? Thank you!!