You're generally considered self-employed if you create and sell custom wigs regularly and with an intent to make money. It could also be a hobby, but from what you described, this sounds like a business. You should expect to receive a 1099-K from CashApp, and you can use this 1099-K to file as self-employed with TurboTax. Make sure you report all the income you receive from selling custom wigs, regardless of whether it's reported to you on a 1099.
There are a number of different rules to be considered for whether you qualify to claim dependents. You can read more about that here!