I’m assuming we are talking pre-school?
I’ve seen some amazing kids who seem to have natural balance and can go a scooter / balance bike not long after they are walking; but i’ve also seen some who don’t get it, and actually don’t have the motivation at that age. I think the worst thing is for you to be forcing her to do it – if she wants to play on the scooter/bike fine; but since she “doesn’t want to practice” I assume actually she just wants to play and the skill development is not yet important to her. So find something else to do.
A fine line between proud and pushy parents, and from what I can see bikers, skiers, and swimmers are all overly eager to boast how great little johnny or jemma is, ignoring the fact that at the same age they probably didn’t even own a scooter…
My eldest son (now 7) is OK on a bike and is probably about normal ability, took a bit of effort to teach etc – and showed no real natural talent (a bit like his dad). My daughter (almost 3) is good on a balance bike and would probably ride a proper bike with little extra practice if we found one with the right geometry.
That does lead me to my final point – if you are expecting her to improve make sure she has a decent tool which inspires confidence, e.g. steering that is smooth, brakes that work with little fingers, tyres that aren’t so flat they barely roll etc.