(SSI)Will I receive a stimulus check if my aunt’s name is on my direct express card? She is my representative payee? I’m 62 years old.

Most likely, but the IRS has not provided guidance on this specific situation. However, The IRS rolled out the "Get My Payment" tool here. According to IRS.gov, you can use the "Get My Payment" application to:

• Check your payment status
• Confirm your payment type: direct deposit or check
• Enter your bank account information for direct deposit if we don't have  your direct deposit information and we haven't sent your payment yet.
• Receive paper check payments: If you moved since you last filed, let us know your new mailing address.

I received SSI and I don't have a bank account but I received direct express where my money goes on every month why is it getting mailed

This FAQ site should answer your question.

https://www.irs.gov/coronavirus/economic-impact-payment-information-center