Age Restriction In My Salon

I own my own salon and currently have no renters at the moment. It’s just me and I’ve owned my buisness for two years, but have been a licensed cosmetologist working behind the chair for ten years.

After some consideration, I’d like to enforce a age restriction on my chemical services such as color, highlights etc. The age restriction is they’d have to be minimum 20 years old. Am I legally allowed to enforce this?

My reasoning is almost majority of teenagers coming to me do not understand the processes or clearly aren’t listening to me during our consultations. They’re going against my professional advice and I am extremely thorough in consults. I am in a high end area/long time in bizz/have tons of color experience and my prices reflect that. I’m usually able to work with a budget, but this age group banters with me about it quite a bit. I will tell them what’s going to happen if we do XYZ and then they want to do it anyways and then they’re unhappy. They’ve become so exceptionally picky and unrealistic on top of it. Regardless of me being very thorough and honest about expectations, I just don’t want to deal with it anymore.

I know I legally have the right to refuse service whenever I see fit, but I’m looking for reassurance to state this restriction in my policies.