We need Michael769 to chip in here...
I had not heard of asking for quotes spoiling your pitch for the future. I would just go to one of the comparison sites (confused.com, gocompare, moneysupermarket etc.) and fill in a quotation - that will get you quotes from up to 200 different companies and I can't see how doing that once is going to affect your premium in the future. If you don't ask, you won't find out
Sadly for you, the rules changed because previously with you being female, the premium might even have gone down, regardless of your inexperience. Now, your age is more likely to be the biggest weighting factor, rather than the newness of your licence, since as an additional driver, you don't bring any insurance history with you. At least, having just passed, I assume you have had no insurance claims (at least in your own name)?
As for looking for a car - do you
want a car? If the answer is no, and from your comment it sounds like it is, really, then no, don't saddle yourself with the expense. The only reason for doing it would be to build up no-claims history, by having a policy in your own name, so that when the day comes and you
need a car, insurance will be cheaper. However you still end up paying money for something that, by your own admission, you may not really use.