Dd (10 Y5)wears crop tops sometimes but not a school as she was been teased. Things are changing now as the main child who teased is now giving dd funny looks when they change and telling her to cover up. Dd started with crop tops due to tender nipples so had very little to cover.
The funny thing is if dd is warm she becomes some what larger in the bust area and could fit a bra , but if she's cold she's not far off been flat chested. Her crop tops are getting a bit tight for her but not sure about moving her on to a bra yet. Plus no one else wears a bra or a crop top mostly because those who have get teased.