Will I keep growing and developing? I'm eighteen, I have one tubular breast and I am incredibly unsymmetrical

Asymmetry in size and shape is very common at your age, when the breasts are developing. Usually, a level of maturity in breast development is reached at 19 to 21 years old. At that time, your breasts may be more symmetrical.

 I'm sorry to hear about your concerns but online consultants will not be help you with specific predictions; obviously, this may be one of those situations where only time will tell.  Having said that, given that you are still growing,  even if it is at a slower pace,  I would give yourself at least one or two more years before contemplating breast surgery. Best wishes.

It sounds like you are still growing. I advise my patients to wait at least two years after they are done growing in either height, weight, or bra size before considering any breast enhancement surgery. Being patient might eliminate the need for a second surgery if your breasts change from further growth. To see before and after pictures of women with asymmetry and their surgical results, click on the link below. For more information on this and similar topics, I recommend a plastic surgery Q&A book like "The Scoop On Breasts: A Plastic Surgeon Busts the Myths."