All my kids have grown up around MX. All have ridden bikes. The oldest, now 14, does not ride. She wrecked at a young age on a jump, and just never took a liking to it, she is an awesome competition cheerleader now, so no big deal. I couldn't figure out why all the sudden she was taking a liking to going to the races with us though.......and found out she has many MX followers on instagram, lol. Think I need to make her stay at home!!
My twins both started riding. My daughter, likes to just get out in the yard or field and ride here and there to play around once and a while. I am ok with that, soccer is her thing (although I HATE soccer).
Matthew started riding a bicycle at 3 1/2. a month before he turned 4 was riding the PW without training wheels. I always had a rule, no training wheels. You can ride a motorcycle when you can ride a bike. I got him a mini adventure for his fourth birthday, and was racing a month later. I have never pushed him at all. He plays football, basketball, and baseball until this year. He shines at football and basketball, but his love is racing. 50s he did OK. 65s he did OK. Now on 85s something is just now starting to click, and he is figuring it out. He has won 5 of his last 8 motos. But once again, I never pushed him at all! He had a bad get off at Briar Cliff this year. Did not want to go back out for his last moto that was shortly after his get off. He was beat up, but NOT hurt. I pretty much made him get back on the bike and go to the starting line. Best decision I made that day. Once he got back on the line and took off, he was fine. Did not ride like I knew he could, but was back on the horse that threw him off, quickly. I explained to him if you ride dirt bikes, your going to fall off dirt bikes!!
He gave up baseball this year so we could ride a little more, and it has paid off. He will still play football and basketball. I am not going to be a parent who races 24/7 and my son is burnt out at 12. Many kids get much faster in their teen years, and it is just a hobby any way.
Just make riding fun for them. Once you make it feel like a chore than they will not want to ride again. And let them go at their speed, not yours.