They did it intentionally, but I'd guess that yes, they do not want to do age makeup.
Funny enough, the young doctor on Deep Space Nine, Siddig El Fadil (later anglicized to Alexander Siddig) Was originally sought after for the position of station commander.
When he showed up to audition, they realized he was far too young for the role, and made him the doctor.
His uncle is also a Star Trek alum, you may have heard of him. Malcolm McDowell.
Siddig was also in previous Dragon show, but they gave him golly all to do.