Well look at different brands, try them and if there's nothing you like then get custom. Its important that your boots are comfortable. And also mountain horse tall boots are really good so try those too.
I got a semi custom pair, im 4'11 full grown and have big feet and short legs, I haven't found anything off the shelf that fit! I did the semi custom Tucci boots but Deniro has alot of semi custom boots! Semi custom is better if you dont want to pay for complete custom.