She's right. After having a major surgery, your body is too busy fighting off infections at the site of the surgery, and doesn't need the added stresses of redirecting antibodies to a brand new open wound. I would wait at least a month after you are fully healed before considering a new piercing. If I recall correctly, the piercer will even ask if you've recently had a surgery, and may deny you if you're not completely healed yet. The piercer's first and foremost concerns are your health and their health, and in your condition, you might pose a risk to both yourself and them.
To answer your second question, it does hurt, but only very briefly. If you've ever had your ear lobe pierced, it feels much the same way, except instead of "pressure and a little pinch that lasts a millisecond" (the pressure is the needle pressing against your skin, and the pinch is when it actually breaks the outer layer of skin. You do not feel it passing through), it's "a little pinch that lasts maybe three milliseconds" (there is no pressure since the cartiliage is firm, and there's nothing squishy to condense. The pinch will last a little longer since it must break through the skin and the cartiliage, but once that's done, you won't feel it pass through either). The pain itself will last no more than an entire second. The pain is minimal (I have a very low tolerance for pain, and am almost brought to tears by merely stubbing my toe, however, to show you how painless it is, I've had a total of 8 piercings, ranging from the time I was 4, to two months ago [I'm almost 30]).
A cartiliage piercing needs more care than a standard piercing. First, ensure you get it done by a professional piercer. Do not allow a piercing gun to be used on your cartiliage (they are designed for earlobes only, and cannot be properly sterilized. A one-use prepackaged disposable needle, or a needle that's been sterilized in an autoclave is the safest way to go. A gun will compress the cartiliage in your ear, will make it hurt a LOT worse, increase the chances of giving you keloids [think of a pearl in an oyster, with the surrounding ear being the oyster and the now-shattered cartiliage as mother-of-pearls], give you cauliflower ear in the area, and run the risk of catching a nasty disease). Second, keeping the area clean with kosher or sea salt solutions and antimicrobial/antibacterial soap is extremely important during the healing stage, as the area can be prone to becoming inflammed. Third, cartiliage piercings take the longest to heal, at minimum, three months, and any little bump or aggrivation can be quite annoying. Fourth, learn to sleep with your hand under your head (on the ear, but allowing room by spreading the fingers around the ear so the piercing can comfortably rest, is how I've learned to sleep), or on your other side, because it'll hurt sleeping on that side for quite a while. Fifth, brushing/combing your hair will prove to be quite a challenge the first month as brushes and combs seems to be attracted to the captured ball ring ^_~. Sixth, if you want a large gauged earring, ensure that's what you pick when you get the piercing done, as stretching does not work with cartiliage, and if you want a larger gauge after the fact, you'll need it repierced. And finally, seventh, to ensure your body does not reject the jewelry, choose a "surgical steel" captured ball ring. Anything less runs the risk of infection, rejection, or allergic reaction.
The pro's? It looks absolutely cool, and is well worth the hassles of the long healing period.