I found out when I was young that whatever new sport you decide to try always (if possible) wear a helmet and watch out for trees! My sister and I were given a new-to-us bicycle once from a neighbour who had outgrown it. Of course my sister being taller than me (and younger) decided that she should be the one to have the bike. Since it was a 24″ bike and I was too short to touch the ground when I sat on the bike in her mind it was hers.
So, not really knowing how to ride a bike my sister bravely climbed on and started to petal… she did really well for about 30 feet (all downhill) until she decided it was time to stop! She didn’t know how to do that though because she didn’t wait long enough for anyone to tell her before she took off on the bike. So not knowing what to do she quickly decided the best way to stop might be to just run into a tree. It worked! Thankfully she only had a few scrapes and bumps. Yes, she did end up keeping the bike. Lucky for me my dad found a new-to-me 20″ boys bike that was just perfect as I could sit on the seat and touch the ground! Being a tomboy I thought it was the best bike I ever had as it was totally indestructable even when you crashed it into ditches!