Thoughts From Experienced Nurses Needed

I'm a new nurse, still in my internship. While I don't have a problem with the fact my preceptor is 15 years younger than myself, nor do I think she has a problem with our age difference, my issue is with how the younger nurses act on the floor. Quite frankly, they seem full of themselves. Sure, nursing is a tough/important job, but they constantly act like they're perfect, always pointing out others mistakes. In the few days of my internship, I'm already feeling frustrated. One nurse with over 30 years experience who's in charge of the internship program told us we will all make mistakes and if you don't, it's because you're not doing enough things. She's right. I don't know what it is. IV's especially drive me crazy. I always do dumb things like clamping off the line when putting on a new bag and forgetting to unclamp it to infuse or not clamping it and losing a bit of what's in the bag!! It makes me so mad at myself. It's especially hard to focus when patients have visitors. It seems they watch like hawks or ask the most questions. The less they are related to the patient the worse they can be!! I guess if I had a preceptor I could connect with, I'd be happier and more willing to discuss my feelings, but mine whines everyday like she hates what she does. I must say she often says what a great job I and another intern does, so I'm well aware things could be far worse, but I just wish the pettiness would stop. Also, I would love to take lunch away from the floor, but feel obligated to eat lunch with others in the breakroom...with all the complaining. I don't want to be viewed as a snob. I just like to get away from things, call my kids/husband and with only 30 minutes, don't have much time to do what I want. Any ideas how to get through this without being so tough on myself? I realize much of this is just part of life. Thanks.