I am in my late 20s. I've been using Retin-A 0.05% for acne since I was about 15 years old. While it did help my skin all those years, it never did completely clear up my complexion. I lived through my teen and young adult years with oily skin and at least one new zit each day.
Do not assume that Retin-A will clear your skin up completely; it won't. But it will prevent you from becoming a bubble face that is constantly exploding with zits that then become huge pock marks later.
Now, in my late 20s, I decided to move towards a more natural lifestyle and get away from meds. I consider Retin-A to me a medication, and it does have side effects, including severe consequences for your unborn baby if you become pregnant. Well, I'm married now and I could become pregnant, even though I'm on the pill. So, about 3 months ago, I quit Retin-A cold turkey.
And my skin stayed the same. Zero changes.
My skin went from oily to normal when I went on a low-carb diet 8 or so months ago. Also, when I went low-carb, instead of getting at least 1 new zit per day, I had 1 new zit or fewer per week. That's really what clears my skin. Low carbing. I aim for 100 or less grams of carbs per day, but the fewer I eat, the better my skin is. Turns out that I also have high DHEA-S. It's higher than the normal range. And I have hyperinsulinemia and insulin resistance. So my acne is, and has been for many years now, caused by my body's intolerance to carbs. I never even needed to use Retin-A.
If I had been on a low carb diet my whole life I wouldn't have had acne. I am sad I wasted my time and money on Retin-A when I didn't need it.