Oh man I can't believe I missed this thread until now.
My daughter has followed in the footsteps with enjoying Star Trek, and she's seen everything up until Enterprise. She's 13 so Enterprise would be ok, but I'm afraid those scenes will be awkward. I haven't watched it since it aired.. am I making more of it than it was?
Common Sense Media says 8+ but that seems awfully young for some of those shameless scenes.
It's not terrible especially by modern standards, although I do remember being 13-14 when it aired and being a bit embarrassed I was watching it with my parents. It's more cringey for being gratuitous than it is anything else. You can have a fun talk with her about bad storytelling and shameless pandering afterwards and turn it into a learning experience.