Yes, you are able to file just the federal return now and the state later. As long as you have not already paid for your state return (or registered your free version with the state attached), you can delete it. If you delete the state forms now, you will have to re-enter that information when you are ready to file state.
NOTE: You do have the option to pay for the state return now, and when you get ready to file, check the I'm not ready to file checkbox for your state and proceed with your federal return. Later, when you are ready to file your state, just go through the File section again.
See below for steps on how to delete the state return, if you prefer to just delete it:
https://ttlc.intuit.com/replies/3301384
