It sounds more like you are just wanting to talk with her. If you were really just after advice, you would just post your request for advice in a question and get a wide variety of help, some of which likely would be even better than hers. Plus, to make sure that she sees it and hopefully answers, you could use the feature of specifically notifying her and requesting her opinion.
Well she has the ability to not respond to the message or ignore it. So if its not her cup of tea she'll either do nothing or politely say so. Personally I don't feel comfortable talking with teenagers in private given the age gap. As advice perhaps sure but if they want to flirt the age gap makes me uncomfortable. Because frankly I have grand children their age.
You can actually invite people to answer your questions now, so if you put all of the details you need help with into a question here and invite that person, not only will you get her opinion, but also the opinion of many other people here.