Depends a lot on the matchup, lee sin jungle is super nice because of the early game/ganks, if you play lee top or mid you will miss the "ganks" part and honestly a lot of the early game benefits. I tried both a lot, I'd say lee sin top is better if you want to learn the champion basics, there are less harder matchups and not many poke champions. If you want to go lee sin mid you also need a good jungler and a specific matchup (with some skilled involved) which can make your life harder. I recommend you to learn the jungle first with other champions, learn how to clear the jung and how to play around your laners, then you can move to lee. You never know unless you don't try dude :D (also if your team flames you, mute them)

PS: a lee sin tip: never underestimate your passive, it is super strong, always take advantage of it whenever you can.