My girlfriend’s developed earlier than I did. I get teased by everyone. Should I have plastic surgery?

No. First you need to see what is going on hormonally in your body. You should see a reproductive endocrinologist to get tests run to see if there is a reason first. If you were to have surgery and then have further breast development it would not be a good situation.
It depends. Don't know your age, but, if you are referring to breasts, everyone develops differently. It would be best to be patient and discuss your concerns with your pediatrician/physician. If all is else is normal and after age 18-21 you are still concerned, consult with a plastic surgeon to learn about your options.
Breasts. Everyone develops breasts at different rates and at different ages. Be sure to express your concerns regarding breast development to your primary care physician. If appropriate, an evaluation by an endocrinologist may help determine if any treatments may benefit you. If everything is normal from a medical perspective, after you have completed puberty, you may consider a breast augmentation.
May be but... If your breasts are smaller than you would like them to be and you have fully developed, you may be a good candidate for breast augmentation surgery. However, make sure your motivation is “internal”, and not influenced by your “friends”. Also, make sure you understand the pros/cons as well as the potential risks/complications associated with breast augmentation surgery.
Get a consultation. If this is something that bothers you a lot, you can start by having a consultation with a plastic surgeon. Go from there. Good luck from nyc.
Plastic surgery. Having surgery is a big deal and something that can have life changing affects. You should never have something based on what others think you should have. If you truly are interested you should sit down with your doctor or plastic surgeon and go over the risks and benefits of a procedure. Then sit down with loved ones and make an intelligent decision based on whats best for you.