My voice used to crack, but I get the impression that it didn't crack for as long as a lot of teenagers' voices do.
@Elijah and others--Sixteen or seventeen months on a full dose, I started cracking again and went into baritone range. I've gotten a couple of small shifts since then--just little changes that nobody else would notice--but that suggests to me that more change is still possible. After all, cis men's voices do evolve over the years, so I expect that ours will, too.