There's no problem with planning your future, but I've watched SEVERAL people obsess over a wedding before there's even a potential groom in the picture. Here's the problem with that-- the focus is obviously on the bride and the fun of getting married and not actually the marriage. Part of the reason why I don't care about and would opt out of having a wedding is because of where my focus lies. I'm more concerned about having the right mate and not the perfect dress, flowers, or reception playlist. I know that once you're done entertaining all the well-wishers, you have to go home and maintain the vows and relationship itself. THIS is the focus.
In planning your wedding while single, you have no way to take into account, the groom. Some would say that the groom will just go along with the plans anyway, but the point I'm trying to make is the amount of thought that goes into the wedding planning should be the amount of thought that goes into the "partner planning". Is he the man for you or is he just the one that asked you first? Will he be a good partner? Is he consistent and stable? He is more important than the dress or the venue.
Just think about how different things would be if couples obsessed over their marriage being perfect as much as they obsessed about the wedding being perfect. The effort and lengths that people go to to make things turn out perfect for their big day should be the same when trying to have a successful marriage. If you are planning your wedding without a groom in sight, there's an element of "any man will do" in the mix and that's not where you want to be even for a second. Maybe you're saying, "I know the man will be good if I marry him", but if you aren't saying the same about the wedding and obsessing over the details well before it's necessary, shift the focus.
Take step back and visualize your perfect marriage and mate. The wedding will mimic the energy of the relationship, but you have to nail the basics of what's required to have a successful marriage. ...Something to think about.