I think it's fine to post about 3D Gamemaker here, or in the DarkBasic section, really there's no other suitable places.
But really your gonna have to come up with a limb hierarchy animated model, with your face textured on it. That's a lot of learning right there.
I think thats a bit overkill, if you want to personalize things, then I suggest you change the textures, but look at other things you can do - like recording your voice and replacing a death sound effect maybe. Imagine adding yourself as an end game enemy, and have a funny message that'll make your kids laugh when they end you.
There's tons of textures to play with, maybe you could even create your own from scratch - but really I think learning to model for this is overkill, unless you intend to progress onto more complex things with your kids, in which case it's a good idea.
Stop-gap solution would be to just make a big head based on your own, get it looking like you, and stick it on the head as an extra bit. It's been so long since I played with T3DGM, not sure how it all works.