I love the look of that haircut! Are you allowed to email your T? If it were me, I'd email her about it so I wouldn't have to worry about that first look she would give me when she saw my hair. Or I'd call and tell her before my appointment so I wouldn't panic! I'm not sure what you could say, though.

Maybe: T, I cut my hair and it looks almost exactly like your hair style. I'm embarrassed about you seeing it because I don't want you to think I cut it just because it's YOUR hair style. Though I like your hair style....

That could be an awkward conversation but I'd want to do it anyway, because it's easier via phone or email. I also think T will be flattered, and not think you're creepy but I can understand your embarrassment and/or fears.