Frustrating movement

My granddaughter really loves Freefall - we’ve played almost every day since it came out. We’ve unlocked all the courses and cup races. Our biggest issue is that we can’t seem to control the up/down (we end up crashing into the ground A LOT and after the first day we weren’t able to get the coins or nuts anymore) and the speed seems inconsistent- we put our hands all the way at our sides and often after the first few seconds everyone has passed us and we are running 8th and 9th… while we still love playing, I’m sure it won’t be long before she gets frustrated with being last.