Should I go on roller coasters if I'm scared?

So, basically, I'm going with my friends to six flags in nj in 2 weeks. so i don't want to seem like a scary-cat and chicken out, but i really don't like roller coasters. i mean, i guess i just hate the feeling of the drop. the "toughest" one i've been on is the rock'n roller coaster in hollywood studios in orlando. and my friends want to go on rides like kingda ka and nitro and el toro. i kind of want to face my fears too, because i know i won't have a lot of chances in the future with going on these types of rides. but do you all think i should do it?? i've watched the pov front row videos of kingda ka and nitro on youtube and kingda ka doesn't look bad ... but nitro....with the drops.....so what should i do? please help!