It definitely can change, and I actually think it should. Even though your taste in fragrance changing may sound a little scary or like indecisiveness, it is actually a sign that your nose is developing. On the homepage of my site, there is a section called Palate where I talk about how fragrance taste can evolve over time. This is not something completely objective, of course, but it is often the case. As you smell more perfumes, fresh and sweet fragrances can start to feel less exciting than they used to, and that is completely normal. A simple example is this: if you do something 100 times, eventually you get bored of it. The same logic applies here. There are so many fresh and sweet perfumes around, and since these scent characters are generally not very deep, after a while your brain, or maybe your reward system, starts feeling satisfied with them and begins looking for something more. So basically, just know this: if your fragrance taste has never changed, there is a good chance you simply have not smelled that many perfumes yet. Or maybe you have already reached enlightenment.