I use my first name on youtube because I want to retain a modicum of anonymity - I.e., I don't want everyone to be able to find me, where I live. where I bank, my personal facebook etc. Not using my last name helps with that I guess.
I tell my daughter not to use her full name online either for the same reason, she is a girl and will get harrassed at somepoint, so will I probably, and I want her to at least feel safe at home if that happens.
Rose is a nice name, why don't you come up with a play on that. Caitlin Thorne or something.
A look around google for Rose Synonyms...
Rouge
Rosette
Blush
Pink
Rosela
Rosalia
Rosalie
Roz
Bella, Rosalba, Rosabella
Rosanna
Primrose
Rosina
Rosy/Rosie
Suri - Persian for rose
Ruza - Croation
Róisín - from gaelic.
Or actual names of rose varieties.. that might be worth a try
Hope this helps