Can i change my filing method to direct deposit without fully filing my taxes this year? I'm still waiting on my newborns SSC, I would like my stimulus check asap though.

When was the baby born?   You say "newborn"---if your child was born in 2020 you cannot claim the child on a 2019 tax return.  Or are you waiting for the SSN so you can claim a child who was born in 2019 on your 2019 return?  

Changing your direct deposit information and not filing the return will not help you.  Unless the return is filed, the banking information is not transmitted.

But please read---there will be a way soon to give your banking information to the IRS.  As for getting your stimulus funds ASAP--you will get them when they are issued.  TurboTax has nothing to do with how fast you get that money.

https://ttlc.intuit.com/community/tax-topics/help/how-will-the-stimulus-package-impact-me/01/1393859#U1393859