It’s fine as is. I climb a bit, and have two kids on competitive rock climbing teams. The layout there is fine for younger kids, but also don’t be afraid to mix things up and rearrange the holds from time to time if you feel like it. That helps keep things interesting. I hope your kids have a blast climbing on it!
If the holds are secured with lag screws (that’s what those types usually come with), they may get loose over time if they see lots of use. If that happens, you can either just move the hold to a fresh spot, or replace the screws with t-nuts and socket head Allen bolts (3/8-16 thread, 2” length).