Adult Tooth (canine) Coming in Behind Baby Tooth at 21 Years Old

I have a retained canine baby tooth on my top set of teeth. I am 21 years old and at this point my adult tooth is starting to erupt behind it. I went to my dentist last year and he recommended that I pull out the baby tooth and along with braces, attach a chain to pull down the adult tooth into place. However, since I am 21 and starting my career, braces is really not a good option for my professional appearance. As well, my baby tooth is still relatively strong and doesn't show any signs of coming out (It has been about a year since my adult tooth erupted behind my baby tooth). I don't really experience pain, just mild discomfort from time to time. It doesn't bother me now, but I'm trying to think of the future when (and if) it does fall out. The adult tooth right now has barely erupted and is taking a long time (it barely grew at all in a year) to grow out, it is basically 1/4th the size of a normal tooth right now. What are the chances that if the baby tooth does fall out, the permanent adult tooth will naturally move in? The dentist I went to (about a year ago) said that it is too far to move into place naturally but I would like a second opinion. At this point my first choice is just to wait it out and see if my baby tooth will ever fall out. If it does fall out, I will just leave the adult tooth as it is without any intervention (it is quite far back, but how bad could it really look?). I have also considered (if the baby tooth falls out) to pull out my adult tooth and just get an implant in place (it would be much cheaper and convenient than getting braces for 2 years). My other option is to get invisalign or braces if all else fails. What do you think is the best route to take?