A UGMA (Uniform Gifts to Minors) account belongs to the minor, not the custodian or the parent. The income from the account is your daughter's income, not yours, and has to be reported on her tax return. You should amend your tax return to remove your daughter's income.
The Social Security number on the account is your daughter's Social Security number, and the form 1099-B that you received for the sale of the mutual funds has her Social Security number on it. It's her money, and the income from it is her income.
Depending on what state you are in, and when the account was opened, it might be designated as UTMA, Uniform Transfers to Minors, rather than UGMA. But the rules are the same.
