Hi there, o.t-rainbow! :)
My name is Autumn and I hope that I can help answer your query. :)
So, I'm from the state of Wisconsin (which is in the US), and here it would not be considered rude to make a comparison with one person to another, generally speaking.
Also, though. it's very common in Wisconsin, if you say someone looks like another person, to say what part of them looks like that person.
For example, "You look like a girl I know back home. You have a very similar nose." It wouldn't be rude to exclude the part about how the person looks similar, but be prepared for people to ask you, "How do I look like them." And like Wik mentioned up above, remember to try and only compare in positive ways. :)
Anyways, this has been my experience as a Wisconsinite, and generally comparing people in Wisconsin isn't considered rude or unkind.
I hope this has been a help to you! :) Good luck on learning! :)
Autumn