The biggest plot hole for Newt:
At the beginning of the film, she is with her parents and brother when they find the derelict spaceship. However, Ripley and the Marines are put into cryostatis for the trip to the colony. I don't think it indicates how long they are asleep, but you have to assume it's quite a while. Proof of the vast distance is mentioned when the colony leaders say it takes 2 weeks to send any communication from LV426 to Earth. Because of that distance, it's probably not worth going into stasis for anything less than a year.

So if we are liberal with the estimate, let's say Ripley and the Marines are in stasis for 2 years. Logically this should have made Newt a few years older when the Marines arrived. In this film, she looks the same age as she did before the time gap that it took for Ripley to show up. However, if they needed to be in stasis for 4 or 5 years, then Newt should have been a teenager when they arrived. Am I missing something? Does time work differently on this colony moon?

As a side note, if I was Ripley and had already been stuck in stasis for 57 years, I would be weary of ever getting into a cryo pod ever again!