I am thinking about buying a dirtbike I am 14 and about 5' 5" 105 pounds. Would use it for a gravel road and 4-wheel trails. Need to figure out how much cc i want. I was kind of thinking 150 but not sure any help would be great, thanks

150s are a good size. Have you ever ridden one before?

4-Wheelers are better for gravel roads and "4-wheeler trails"
But for dirtbikes if you are 5'5 and are only 105 then you need somthing like a 100

I wouldn't go as low as a 100, it wouldn't take long for you to outgrow the size of the bike and also be wanting more power. The lowest I would go is a 125, but thats when you start getting into supercross and motocross riding styles, as most 125 aren't geared for trails but more for tracks. If you are wanting to strictly ride trails, I would say get a fourwheeler, but not a utility. Utilities are fun and all, but riding a manual fourwheeler is funner, imo. Honda makes a 300EX thats really great for people that are first starting out, they don't have unbelievable power like the 450s and 700s and you can mod them out to give you extra power and speed as you desire until you are ready to step up to the bigger machines.

ya ok I think I think I'Ll go 150 thanks for the advice

Well whatever you decide to get, be sure to wear helmet and other important safety gear. True, your friends might make fun of you and say you look dumb or whatever. But my logic is simple; Better dumb than dead.

ya ok will do