Hair coloring. First trimester.

Samantha
Hey everyone. 
I was wondering if it's safe to dye hair. I'm currently 9-10 weeks (haven't had my fist appt yet, I have it January 8) 
I have blonde hair but wanna color it back to dark brown due to my roots. And plus it looks better in me. 
Just want to know if it's safe or not. 
My mom said no (she's a cosmetologist) but I'm not sure