Have you ever drawn a comic? I mean, really tried to, paying attention to composition, pacing, the merging of storytelling and art? If you haven't, I suggest you choose a short story and try to draw a comic about it. That should give you a fair idea of how naturally drawing comics comes to you. If drawing that short comic feels like torture, maybe you should reconsider. If it comes naturally and feels enjoyable, go for comic-making. Even if you are not that good. Skills can only be honed through practice, and you might be great in five years.
As for realism versus "manga style", that's a style choice that's yours to make. Personally I prefer semi-realism.
As for drawing classes, take them. Even if you've drawn for years, you might learn useful tips etc. Besides, when you draw for yourself, you easily slip into routines. For example, always drawing faces at a 3/4 angle. You have also only mentioned drawing the characters. A comic artist should be fairly good at drawing everything that might show up in the comic. Can you draw backgrounds? Urban settings, suburban settings, rural settings? How about three different looking cars? A coffee pot, a chair, a hairdryer? In a comic, the backgrounds matter. You don't want your characters to exist in a limbo, but neither should your backgrounds eat your characters. The more you already can draw, the less there'll be searching for references when you're drawing the comic, thus leaving more effective drawing time. Classes are not necessary, but then you'll have to challenge yourself and get critique from somewhere else.
Those are some things to consider and should give you a fair idea of how hard even making a comic can be, let alone publishing it, getting recognition, scheduling your days to include both comicmaking and a supportive job (if you're thinking of making a career in comics). It's not easy, but if you like it enough, why not try to go for it.
And remember, equipment does not make an artist. An ugly painting is an ugly painting even if it's painted with the most expensive oils you can find. Learn to use basic equipment, learn what you want them to do and only then buy those expensive superawesome markers or whatnot. You can have a $500 pencil and not be able to draw one straight line. It's you who are drawing, not the expensive pencil.