Serafina had completely outgrown her bike by the time she got one for her birthday. Leo was in the same boat. He would ride my bike instead of his because it was too small. He wanted a nice mountain bike for his birthday and Tom found a good one that he ordered online and was delivered to our local sporting good shop. He wanted to give it to Leo early, just like Serafina got her bike a little early. After I picked Leo up from school today, we ran a quick errand and then I headed to the sporting good store. Leo was blissfully unaware where we were going because he was reading in the backseat. When I pulled into the parking lot, I saw Tom riding around on the new bike. I said to Leo "look at that grown man riding a kids bike. What a weirdo". Leo finally looked up and said "hey, that's dad. He rode his bike here? Wait, that's not his bike." And it all clicked and he got very excited. Tom was nice enough to dismount the bike and give Leo a turn. He was really happy with it.
And yes, it is giant. It's bigger than my bike.
We went back into the shop to have the bike guy check out the sizing, but he assured us Leo would be just fine on this size while he grows into it.