Don't be sorry for liking Britney. If you like her music and it makes you happy to listen to it, then you're right to like her.
Having said all of that, I'll give you my humble opinion. Having grown up in the 60's, I was exposed to a wonderful mixture of rock, soul, earth shattering song writers like Dylan and Lennon/McCarthy. I thought these guys were modern day gods. My parents though they were meaningless noise.
Now in my mid 40s, I see Britney on TV and think to myself, "Gee, she doesn't have a good voice, write good songs, and she lip synchs on stage. It's more about dancing and Vegas-like production than it is about music." But then I have to remind myself that my folks thought my music was garbage.
The moral of this? It's all relative. If Britney moves you, if listeing to her gives you enjoyment, then it's good music to you and that's all that matters.
Rock on.