OK, so i am 19 and I have biggish boobs - a 34DD. I don't want them to sag as i lose weight!!!! That would stink!

Any tips/suggestions?

Gravity is what makes boobs sag. Also, for awhile, while your skin shrinks up, they might sag a bit, but being as young as you are, they will more likely shrink up the looser skin than not.

The best way to keep boobs from sagging is to wear a good bra. If you've never been sized, do so - either professional or use a guide online (I'm not so sure everyone in stores knows what they are doing. I've had some wacko suggestions - like wanting to give me a 44 band and a D cup when I was 40G (rib cage was 38.5) And I went in their complaining about the bra sliding up my back!!!!"

Choose a mother whose breasts never sagged!

A lot is genetic. A lot is how much of them you lose. A lot is skin elasticity.

Mine did sag, but I improved the look a lot by working on my chest muscles. They're still imperfect, but they are better with some solid pectoral muscles built underneath.

I second the good bra. I have big boobs and I have to say a good bra makes a huge difference.

Try upper body exercises, especially those for pecs. This worked for me for years, then I got older and they sagged anyway. LOL

1. Wear a good bra. I find that Victoria's Secret bras aren't effective for girls like us with bigger boobs (34D here). Their straps have too much elasticity when you buy them, much less after a couple months of wear. Spend a little extra, go to a department store or somewhere where they can make sure you're wearing the correct size.

2. Drink water and use lotion. It doesn't have to be any special kind of lotion -- the point is to keep your skin elasticity up so that it adjusts to your weight loss.

3. I can't stress this one enough -- do upper body exercises. You don't need to belong to a gym either! Holding your body in a plank (or forearm plank position) is enough to get started. Building up your pecs and upper body will perk up your boobs. I started doing them a month ago, and my boobs are more perky than before I lost 30 lbs. (I've also been losing slow and I'm in my early 20s)

Don't compare yourself to models. Women tend to compare themselves to what they see in the media. Forget what you see on models; many of those women have had plastic surgery.
So have yourself measured and consulted by a professional. Many quality lingerie stores and department stores offer this service for free. make sure the middle of the front actually touches your skin, and make sure to use an underwire.
Feeling shy? That's normal. Bring a female friend, relative, your mother, whoever you feel comfortable with for morale support.