As a resident who always asks this, I want you to be honest.
As others have mentioned, there are some out there who will try to nudge you towards cases that are likely to be interesting to you. I try when I can, but it doesn't always work out and some fields just don't work out. But if I don't know, I can't help you.
The other major thing is, that as a 3rd year, no matter what specialty you're going into, EVERY patient has something you can learn from. I know that not everyone is going to be a pediatrician - hell, I don't want everyone to be a pediatrician. But what upsets me most are the students who think that taking care of pediatric patients is somehow beneath them, boring, or worthless. As a 3rd year, your inexperience is overwhelming and so to throw away an opportunity to get better is ridiculous - especially when you see how many people complain how they don't learn enough on clerkships. Even if the only thing you focus on is doing your perfect H&P in 30 minutes instead of 35, that's going to beneficial for you as an intern.
Lastly as far as choosing lifestyle specialties...I'm going to respect you far more if you can show me how much the medicine actually matters to you. If you go on and on about your salary, the hours you're going to work and the boat you're going to buy, don't expect me to congratulate you. But if you can tell me how much you love Moh's surgery and getting to positively impact the life of a cancer patient, that's far more interesting. But just as you have biases about my specialty, I'm entitled to biases about yours. Sorry but I'm not sorry that as a pediatric intensivist, I feel like saving the lives of dying children is more important than making sure some Junior Leaguer got her Botox and liposuction or that dictating "clinical correlation is advised" on the report for a chest X-ray is somehow the most fulfilling use of your time.