I think you mean a .410 gauge Mr. K, and I concur. I bought my daughter a nice used Ithaca Model 66 super single 20 gauge, and it’s too much for her.
Shoulda went lighter....
My advisor here says that a 20 gauge is half the shot load and twice the kick. And that a 28 gauge is a better choice for girls...the 410 is more of an “expert” weapon.
You might want to get a .410/45 Colt chamber adapter from Short Lane for that Model 66. I ordered one last year for around $20.
.410, .420, Whatever it takes...