I am 10 nearly 11 and I want/need a padded bra. Are training bras padded and how do I ask my mum for a padded bra?

You either want or need a padded bra. Want and need are two different things.

Why?

And, no, training bras in general are not padded.

If you need a bra and your mother is the least bit observant, she already knows that. If "want" is the key word, she also knows that.

Sit down with her and explain your reasons. Everyone here who is someone's mother has had that conversation.

I'm always somewhat amused by padded bras at your age. For that matter I always wonder how women (and this does not apply to you) find a sexual partner while wearing a padded bra, take it off and - surprise! What you saw is not what you get!

Check out this thread:
https://www.askmehelpdesk.com/children/how-do-ask-mum-padded-bra-747319.html

It deals with the same question. In fact, I thought you might be the same OP asking again.