nope, not at all. but be careful if you do try to gain weight, it may go over board as to where going back to your old physique may not be as simple as planned. I'm sure you're beautiful no matter what height, shape, or size! If this is some sort of peer pressure thing (which i'm definitely not saying it is) but if it happens to be, dont feel you need to change to fit in. Best of luck in the size you choose! Have a great day!
Some people agree that they would look better bigger, but its terribly unhealthy and all doctors vote against it. Its better to be healthy than beautiful.