Let me weigh in with a persepective I've haven't seen in the answers -- that of the mom who's done. My girls both trained into the optional levels. Dd1 stopped when she hit the limits of what her body could do. Dd2 just decided one day that she was "ready to be done and have a life".
Just so you know, both kids still love the sport. Dd1 coaches now. We're all still big fans. So, while I've going to give you negatives, please don't think they're coming from a position of sour grapes.
First, finances definitely need to weigh into your decision. Elite gymnastics gets expensive and gets there fast. Can you afford it?
While we're on the subject of finances, let's talk realistically about that college scholarship. Not all level 10s and elites get them. NCAA rules limit the number of full rides a school can give in each sport. Do not EVER think of this as your college plan. If you can't save for college AND pay for competative gymnastics, think really hard about which is more important to you and fund that. Yes, girls get them, but only a fool counts on them.
I also want to strongly agree with the poster who said that in sport, especially for a 6 year old, "right now" should weigh more than "later." Stuff happens. My dd1 is so short, 4' 11" adult height. Great for a gymnast, right? A funny thing happened during puberty. She didn't grow taller, but the girl's got Curves. D cups. She came home from a meet one time and said "how come I'm the only one with boobs and a butt?" What I'm saying is there are things that are compeletly beyond your control. Pick what's best for her health and happiness right now (well, within the next couple of years).
While we're on the subject of health, let's talk about injury. The likelihood that your 6 year old is going to be injured is probably pretty low. And let's face it, falls and catastrophic stuff happens in all sports. What you're looking at that may be unique to sports like gymnastics is the probability, of overuse injury. So, she'll be an elite at 13. How many hours has she spent pounding those growing joints? Dd1 lives with pain in her knees every day. She cannot participate in running sports because her knees can't take it. We've been to all kinds of doctors, all with the same diagnosis. Sorry, can't fix her. Understand this risk (and it's very real) if you take that elite track (Well if you take any track!). Is the reward worth the risk? FWIW, dd2 is fine. Totally fine.
Finally, I want to weigh in on the whole let your kid choose debate. Your 6 year old cannot decide for herself because she does not have the capacity to understand the long term ramifications of her choice. Of course you ask her if she likes what she's doing, but understand that it is your decision.
Letting the child decide is, I think, my biggest failure as a gym parent. WHen dd1's knees started to go, I should've stepped in and said no more. But she loved it. But she WANTED to go. But she could handle the pain. It was HER CHOICE. NO, it was mine. I'm the parent. Even a teenager can't look far enough into the future to determine what's best. It was my job, and I failed. Had I made her stop, she could probaby play any high school sport and participate in any activity she wanted --- without bracing or pain.
Not that you shouldn't go ahead with the sport. Like I said, we still love it, but go into it with your eyes open.
My choice would be option 1, just because I think an elite track is too much, too soon, and too fraught with problems for a 6 year old.