A word of caution (applicable to all “old” bikes) - the bike is around 50 years old, assembled with whatever average grease Schwinn was using on average bikes back then. That grease is probably of little value all these years later, even if (unlikely) the stuff is still clean. So, if you know how, every bearing should be opened, cleaned out and regreased with modern stuff. Otherwise you could ruin the bike quickly by riding it.
If you’re not handy with bearing overhauls, and have the tools, then you pay a shop to do it. That could cost $250 or more. Check that out. Check out the tires and tubes too. 50 year old tires are not safe. Dry rot. And cables/housings. Look at the big picture.
Sorry, but if you bought a 50 year old car you’d do the same or even more, huh?
I had a bike once, made in 1976. The crank was hard to turn. I sprayed WD-40 in the BB which freed it up. Until the next morning when it was stuck again. The original grease had dried to a thick paste, more like chewing gum. Material science has come a long way since 1976.