Yes you are overstepping boundaries
You really need to move. Trainers barn, trainers rules. I am sure that you know a lot but here is the thing, you don't really want her input unless it is something you don't know or it is convenient. Trainer is there to make money and by clipping your own horse she does not, also sets an example to others that hey if you want to do your own thing go ahead! If you don't want to move due to great care 24/7 that most owners can't provide on their own (not all, but most) then you need to have a conversation with her and get to know each other. Maybe she can use you in the barn in some capacity where you feel useful and she does not feel like you are a rogue. I do want to point out to people that even though people pay to board you are still a guest in someone's home, a boarder if you will (for those of you that remember what a boarding house is, for those that don't it's kind of like a dorm). You still need to have manners, clean up after yourselves, make yourselves comfortable but don't let me find you in bed with my husband...lol! In other words, don't cross the line.