Yo, that's awesome and incredibly sweet. There's actually a centralized repository nowadays with all custom levels for the game, here: https://marbleland.vaniverse.io/
Pretty sure you can find your levels on here.
Pretty sure you can find your levels on here.
It was my son's favorite game when he was 3-5, so I started making maps that couldn't be failed, working my way up to some tricky things.
At one point I made a birthday cake map and my wife decorated a cake to look like it. Ring pops for the gems, and an upside down reese's peanut butter cups decorated with icing for the start/finish pads. Of note, putting icing on a reese's does taste good, it is a step too far for human consumption.