Do i need to be good at math to play rpgs?
No ... math-skills can help in RPGs that involve a lot of number
crunching, but most RPGs have options in place, like auto-leveling
and things that help you have fun without having to compute
numbers.
I would stay away from hardcore Dungeons and Dragons games, like
the Neverwinter Nights series. Those games have a steep learning
curve, especially if you aren't familiar with D&D game
mechanics.
But there many kinds of RPGs out there, it's a very versatile
genre. You want to look at hack & slash action RPGs, or
Japanese-style RPGs (like the Dragon Quest or Final Fantasy
series), or even puzzle RPGs like Puzzle Quest.