something I learned along the way: set your objective as "I will type 30 minutes a day" instead of "I wanna hit 100WPM in xx days" cause the first one is more practical and all in all a better mindset to achieve something that needs mileage.
I used to, (read: USED to), average around 95-100WPM waaaaaaaay back in high school. Back in "the day". ("The day", incidentally, is a wednesday, not a whole lot of people know this, LOL).
Now I'm 44, and my typing skills are roughly down to about 80-85WPM. What changed? Time, I suppose. With age, I've slowed down a bit, but I mainly believe it's because I simply do not write many emails or have a need to type at all, other than in-game like World of Warcraft or the like that has a chat feature.
I will say, however, that I think I would have been slower, but here's where my pc gaming background comes into play: I build my last few computers for gaming, an they've all had one thing in common...
...a mechanical keyboard. For all the advancements in tech these days, nothing compares to the old-school mechanical keyboard. So much more responsive, an there is a subconscious tactile feedback that can't be beat.
It used to be only a few scant years ago that mech' keyboards were rather pricey, but with everything in technology, with time the prices come down. You can get a decent mechanical keyboard for less than $100 now. Hells, the very keyboard I'm typing with now only cost me $45, an it's far an away better (in my subjective mind, anyway), than a lot of the pricier, flashier models. I've had Razer boards, the Asus Claymore board, an various other ones, but this has been the best bar NONE. Just familiarize yourself with the various "switches", i.e. Blue, Brown, Red, ect, and I'm sure there is one out there for you. Switch-type matters in what your goal is, if it's mainly for typing, or gaming, or both. Different switch types not only vary in how they feel, but in how they SOUND. Very important for those that hate the click sound of keys, or if you have housemates or SOs that are trying to sleep. For instance, I LOVE Cherry MX blue switches, but they are the LOUDEST of switches, so much so that they can even annoy me after a couple hours.