The type of wheel doesn't matter, the kit will use it too much, even some adult chins have to have their wheel taken away sometimes do to weight loss. Also you don't leave her in the cage for 6 more months, just until she is 6 months (close to full grown), so being about 3 months that is just 3 more you have to wait on playtime and wheel. During that time you can work on bonding, play with her in the cage, read, talk, sing, or even hold her and let he play in a controlled space (not loose in the room) for 5-10 mins a time. Too much exercise when they are little can cause a drop in blood sugar which will lead to seizures and death. So if you want to spend half an hour with her, start out with her in the cage, climbing on you or getting handed chew sticks or something, then a few minutes of play in a small area then back to the cage. With an animal that has a 20 year lifespan 3 months really isn't that long. Also you really aren't bonding when she is running around, most chins pay little to no attention to their humans when loose, so the few months should give you time to get a more solid bond with the chin, which will make playtime more fun for both of you. A more bonded chin is more likely to use you as a jungle gym when out and interact with you more.
Kits are clumsy as you and others have mentioned, they are growing and have growth spurts where they aren't proper portioned at times making running and jumping clumsy at times. So I would thing during those growth spurts they are more likely to end up with sprains and strains when jumping around and landing wrong. Unless you are keeping her in a tiny cage (less then 2'x2'x2') she should get plenty of exercise just jumping around the ledges of the cage for now. Think about the kit right now as a baby, we don't just let babies crawl all over where ever they want, we keep them in playpens or cribs most of the time until they are older so they don't get hurt and don't expend all their energy. Also just like young human babies, chin kits don't need much exercise until they are older, they need sleep, food, water, and to grow.
Another thing you didn't ask about but I wanted to mention anyway, no treats until she is 6months to a year either. She needs only good pellet only food, not treats, to grow. In the mean time you can offer her sticks to chew, different types of hay (handing strands to her), hand feeding pellets, and small toss toys to help with the bonding process if you want to hand her things.