In my experience, few guys get really significant changes in four weeks. They'll get scratchy throat, slight shifts, hoarseness, and so forth. Some guys do get lucky and hit the jackpot right away, but they seem to be in the minority.
It also depends on your genetics and your dose, of course. I hear some guys complaining that they're not getting big changes at, say, three months, and then it turns out they're on a very low dose. Other guys are on a full dose and take that long (or longer) to start noticing changes. And, as you say, everyone's different.
It's hard to fight the anxiety about vocal changes, but try to sit back and enjoy the ride. Very few guys have trouble getting a male-range voice.
One more thing--some of us literally fight the changes and unconsciously keep our voices higher, maybe because it's what we're used to.