There is another side to this issue that is not getting addressed.
My advice is to tread very, very carefully, and to be far, far more concerned about making her feel like an important team member and playing your 'HR Complaint Cards' very, very carefully, than dwelling on how she is attacking your seniority by .... wearing PERFUME.
Keep in mind that some folks wear patchouli to cover up problems with anxiety sweats, or other health problems.
Having been in corporate America for many, many years, I am here to tell you - from the point of view of a harried, hassled, over worked HR person, this sounds like a very, very trivial complaint, you do not have a health issue, you just don't like it. With HR, you get a few 'Aces', like in a card deck. You want to be very, very careful, how you play those aces. Often, complaining to HR winds up backfiring, and making the complainer look worse than the complainee. My advice? BEEEE CAREFUL.
Unless your WRITTEN dress code has a specific mention of use of perfume, it looks even more of a nuisance complaint. BE careful.
If you had handled me the way you handled her, I would ask for a transfer to another department.
Going up to her with your 'patrol' of other women to back you up and prove how you are so right, and make her feel more cornered, and more attacked, was a bad idea. I would be very, very surprised if that tactic worked with anyone - young or old, new or senior.
Going behind her back to HR, ambushing her when she has no idea how incredibly het up you are about this issue or how far you'd take it, is also a bad idea.
She is an employee. So are you. You're also not her supervisor (unless I missed that).
It does not fundamentally matter if you are so senior and she is new. You are members of the same team, and assigned with the same goals - keeping your company profitable. When you start thinking of yourself as 'special' because you have nine years in and others do not, you put yourself on a very, very slippery slope with management, very, very quickly.
You need to find a way to work together and achieve company goals. As a senior person, it is your responsibility to bring new people into the company culture, make them feel welcome and comfortable, and help them do their job. It is your job to keep company goals paramount, and foster the goals of the company above everything else.
My suggestion is this. Hold off going to HR. Instead of mulling over how she is 'attacking your authority' by wearing perfume, and especially instead of talking about it with your friends at work and getting yourself and them more and more indignant and against this person....
...find something to like about her, and think about that. Repeat it to yourself, 'It's great having new folks in the department, they see things differently, and bring new ideas', or 'She reminds me of myself at that age, new in the job market, and learning as she goes'.
Then take notice of her regular duties being done, and praise her. Do NOT overstep your authority to assign work to her, and do not suggest she do something not in her job description. Do not put her in the position of having to decide to obey you vs her supervisor.
Talk to her. 'How was your weekend, Mary?' Expect a sullen response for a while as you have already put her on the defensive. It will take a while for her to relax and trust you. Keep working at it.
If you bring her onboard more, and make her feel welcome and appreciated, she may stop wearing the perfume all on her own. If she does not, once you've built a little bit of a connection to her, then you can talk to her quietly, PRIVATELY PLEASE, don't put her in a corner and don't bring a patrol along.
'Mary, I know we talked about the perfume before, but I don't think I really told you that it bothers me, really a lot. Here's the article in the company policy on perfume. I REALLY don't want to go to HR and complain, but the perfume really bothers me. How about we just take care of this privately, and keep HR out of it? I'd prefer that. We've got a good team we're building here, and I want you to be a big part of it. You've shown a really good work ethic, and I like working with you, so let's just handle this ourselves, ok? What do you think, can we resolve this this way?'.
Then LISTEN.
'No, I don't, all you do is pick on me because I'm new, I hate it and I hate being here'(sobs). - 'I'm sorry we got off on the wrong foot. I made some mistakes and I'm not proud of that. I really hope we can fix this. From your view, what should I change?'
'Ummmm...okay I can stop wearing it. I didn't realize you were so mad about it'. - 'I didn't really communicate well with you. I made it like a sort of joke, and I brought my friends along. I wasn't very honest about what I was feeling. I'm sorry about that'.
'I already stopped wearing it, you can still smell it?????' - 'I think it will wear off in a little while. That's good enough for me. I'm really grateful that you're taking my feelings seriously. I really like working with people who do that'.
Then keep it up - keep communicating, keep building the team, and keep focusing on the company goals. The best teams - the VERY BEST teams in any company, any business, are an eclectic mix of people - young, old, new, senior, formal education, as well as worked up through the ranks. Those are the BEST teams. They don't always see things the exact same way, but everyone contributes part of the solution, and they move far more effectively toward a goal.