I think you've misunderstood. I don't care about what you look like. The point is _you_ have a choice what weight you give it, you can choose to care less or more about it (at some level).
The reason to answer the "so?" question is to understand it for yourself, your answer doesn't matter to me in the slightest.
> find your insinuation that my caring about my appearance and style is "immature" a little offensive. //
I don't think it's immature to care about one's appearance; I do think it takes a particular development of character - that usually comes from maturity - to feel a desire to conform one's appearance to a particular pattern but look beyond that, and learn to accept it.
Along with that I'd note that appearance is often all-consuming for teenagers, and less important for most people as they age (things like functionality and longevity, say, become higher priorities than the simple look of a thing).
All that said, I'm not sure why you're so hostile to my opinion: as you say your life is not mine. If you're content in that then that's showing just the same sort of developed, mature, thinking.
[TL;DR] So, I merely suggest you answer for yourself why "I enjoy looking good" and _consciously_ decide on the weighting that has in sartorial and other aesthetic decisions.