I want to start playing RPG's. What do I sart with?

[GooseGaws]

As you seem to like Mario games, I will echo LNRT in recommending one of the RPGs in that series (SMRPG, Paper Mario, Paper Mario: TTYD, Mario & Luigi series). They are fun, easy to get into, and extend a world that you are already familiar with. After that, if you want something a bit meatier, move into FFIV DS or FFVI GBA. Or, if you want to get REALLY crazy, some Shin Megami Tensei PS2 games.