i dont understand this post at all.
naturally, the order of things is as follows :
if you think you're too skinny, you probably have thought about bulking.
if you think you're too fluffy,chubby,fat, or otherwise, you have probably thought about getting skinnier.
since you mention the option of cutting, i assume you find yourself to be overweight, but trying to decide on whether to cut or take advantage of test levels being high.
assuming the above is true, you have to decide whether you would feel comfortable being a fat guy with muscle and no definition. personally, i would suggest cutting first. why? because it doesn't take as long. also, you mention that your testosterone levels are at their highest. Testosterone not only builds muscle, it also burns fat. you might want to look at that fact as well [ when thinking about taking advantage of peak levels]. this translates into easier fat burning as well as easier muscle building. so you really need to decide what is more important for your goals.
at your age you can get rid of fat fairly easy. dont eat crap, and exercise a bunch. its not like you have a busy schedule. it shouldnt take more than a couple months. then once you are at a weight you like, lean bulk until your 20s like you say.