I can understand a parent being offended, because they usually think their kids look perfect (once they aren't deformed in any way) Moreso if you inherited her features, and have decided you don't want them anymore That doesn't mean you have to stick with something you're not comfortable with just because they want you to look like them. They might also not want to see you having surgery for something superficial, since all surgeries come with risks. Some might feel that having elective surgery on such a visible part of the body will result in obvious scarring, and would be difficult to cover up if it's not done well.
I don't see anything wrong with plastic surgery. I'm of the opinion that someone should only go under the knife if they absolutely must, and the factors influencing that are extremely personal and usually highly significant to the individual. I want to point out that this does not mean that others believe your nose is too Jewish, and even if they do, their opinions should not influence your decision in any way.
You're a responsible adult capable of weighing the risks that any surgery carries, and you would be aware that the outcome of the surgery could be fantastic, or a botched job. If you do decide to get the surgery done, make sure you shop around for surgeons, find out how their previous patients were treated post-op, whether their concerns were addressed, whether they received good post-op care or were ditched. If you're not comfortable with your plastic surgeon's consultation for any reason (e.g. you feel as though they're bsing their way through it, brushing off your concerns, not being clear about the procedure), do not let him/her operate on you. There's a forum called PurseBlog that has a section dedicated to plastic surgery, with people talking about their experiences, and the names of surgeons they went to (both good and bad).
I don't know if any of your friends or family have ever had plastic surgery. If so, then they would be great sources of information. Otherwise, try and gather as much information as you can, do your research, talk to people online who have had the surgery. If you don't have a good plastic surgeon that you can go to, don't rush into it by using whoever is available. It's worth the wait.