I learned on an automatic and didn't know stick. Did that stop me from buying an old manual Mustang? Nope. I figured I had some practice with manual shifting in racing games (console), surely it couldn't be that hard. I stalled plenty of times leaving the lot but once I got it going it was fine. It only really took a couple days of dropping clutch and stalling on hills before I had it down.
Edit- Dang pedants