I never had strong feelings about my name, except that it was the wrong gender.
Like you, I picked a new name that sounded a lot like my old name, just because I couldn't think of anything else at the time. And it grew on me as I used it on this forum. So when the time came to make it official, it sounded like me and I was happy with it.
Things I like about it: it keeps my initials the same, which has already had practical advantages; it is age-appropriate for my generation; my signature didn't change much at all, so learning to sign it was easy; I don't have to explain how I chose it.
So congrats on picking a "starter" name. You might find out you like it. And good luck coming out to your mum. I know it is hard, but you will do it.