Hanon and Dohnany exercises will be good places to start. But it's very important to practice sight reading. That means reading music you've not seen before. IMSLP.org can help, but you'll need a healthy printer. Developing skill at sight reading will help make you a better musician and one that will be useful to others. It will also help you find music you may enjoy learning.

It doesn't sound like you plan to work with a teacher. This is probably a big mistake. Find a good teacher to guide you. Good luck.

You should not practice more that 3 hours per day, and you can easily burn out by being obsessed with learning. Take a couple of days off here and there, and let your mind and hands recover. The brain works with the hands in a coordinated effort, so its not just about how much you can memorize, or what you can physically handle with drills, scales, etudes, etc. The relationship of mind and body (hands and arms) grow together over time with consistent work.

It takes a couple of years to develop your hands for basic technique, and then you will (hopefully) figure out how to further develop your technique, and then a couple more years of more specific training exercises as your mechanics take real form (etudes help here). Its an evolutionary process, and it cannot be rushed.

You will feel great one day, unconfident and discouraged the next. You cannot judge your ability day to day (like the stock market!) But instead take what you can from each practice, and over time it all comes together.

The best way to track your progress (what I do), is every three months, write down a list of the pieces you currently play, what percent you are completed (memorized for a performance) for each, and note what you need to work on for each piece. By the next 3 months, you will see that you have cleared up previous issues, and added more pieces, and improved your technique.

Good luck

Basil Joseph, as others said you will need a good teacher. I've had a couple of good teachers when I was little, but my dad didn't want me to take lessons when I turned 13, so I taught myself from then on. This caused some bad habits that went unnoticed for a long time and when I started taking lessons again a couple years ago, my teachers had to correct my playing.

Also, I would recommend that you spend some time reading history behind the music that you want to play. Not sure if you want to become a classical or Jazz pianist, but since you mentioned "professional pianist" I think the more you know about the music you play, the better performer you will be. Study some basic music theory and history if you want to do classical music. Understanding harmony and structure helps the performance, I think.

As for your age, 22 is not old at all, but then if it is your dream to be a famous classical pianist like Argerich, Perahia and Andsnes and Lang Lang (just to name a few), that may not be possible. A lot of pianists these days start at the age of 5 or younger and they have a couple of big name competitions in their resume by later teenage. And I am not sure if there is any major compatitions that will allow any pianist over 30, so that could be another factor against your age.

Having said all those, if what you meant with "professional pianist" was a pianist who works with a local orchestra occassionally or a chamber group, that is quite possible. You may need to get a performance degree first though, since there seem a lot of musicians out there looking for jobs.

Good luck with your piano career.
Ianholic.

ANYTHING is possible if you believe it. This has been proven many many times throughout human history (often to the discouragement and disbelief of others). If a 22 year old beginner wants to achieve the level of a world class concert pianist there is nothing stopping them if they want it bad enough and are willing to put in the work.

where did you get the idea that you should not practice more than 3 hours a day?
When done properly you can practice as many hours a day as you choose. I did. And I'm glad I did. Art Tatum, one of the greatest pianists of all time, was known to spend upwards of 15 hours sitting at the piano at various points in his career.

Well another guy named Franz Liszt put 10 hours a day into his practicing. So did Glenn Gould, Rachmaninoff, Shumann and Scriabin. I just think to make a sweeping generalization like you did sounds foolish. Everyone is different.
And is you read my tag line it in fact does not not contradict what I'm saying. Think about it......

Oh, some guy named Chopin.

ps...this is not as applicable to technique exercises...