Hey, I never said it was a good idea to snowboard however you want
If you take some lessons, you can probably figure out what stance is best for you.
And hopefully the people renting your board to you will understand to check your weight, not your height when they grab your board. When I first started, I asked for a different board a couple times. They tried to give me a 140 something once. I'm 175 pounds and 6'3. It was like riding a tongue depressor down the hill.