My son was just turned 7! He's a bit of a chicken and every time we asked him to try without stabilisers he didn't want to and tbh we didn't push it cos we have enough tantrums day to day without adding more 😂 Then in the spring when he turned 7 and took his bike out he just asked to try and he was flying along in 5 minutes of the stabilisers being taken off!! I think because he was older he picked it up quicker. They're all different and as long as they're happy I don't care about anything else!
Also, he has too many other ride ons, scooter, tractor etc so I think the bike got forgotten about for a year or so, but since he started riding his bike it's his favourite thing and he's on it all the time!