Ok so your saying I should go to my local flight school (www.flyftm.com) . Take a discovery flight. And if I like it then start the lessons.
You certainly could, if you can afford it. Just how are you planning on paying for this endeavor? Even the cheapest rental plus CFI at the school you posted will cost you $100/hr. I hope for your sake you have very wealthy parents!
At that age most parents probably won't commit grand sums of cash so their pre-teen can learn to fly unless they are well off. Good for you if they are. If they are willing to pay only a portion and you must pay the rest, you need to be budget conscious. Esp seeing as you probably won't have much of an income at that age.
If you are doing this for recreation, then the added cost of starting so early can be written off as entertainment value if you chose toss budget consciousness to the wind. However, if you are wanting to possibly pursue a career, then your money is better saved and spent on future flying when you can apply it to advanced ratings that will move you toward that goal.
Figuring the rate of $35/hr for a CFI and $65/hr for a C152 from their site: if you took an average flight of lesson 1.5 hours long, twice a month from age 15 to age 16, soloed, then flew alone each month for only an hour each month up until you turned 17, then did 5 flights with a CFI for checkride prep the total cost would be $5660 for CFI & aircraft rental.
If instead you studied hard for a few years, then flew rigorously and applied yourself for 2-3 months to take the flight test on your 17th birthday and did your PPL in the minimum time required* your costs for flight instruction & a/c rental alone would be $3,475.
*Of the FAA min of 40 hours (including 20 dual & 10 solo) lets say you fly 25 dual & 15 solo while accomplishing all the other requirements.
That's a difference of $2,185! If you just before your 17th birthday, should be able to get your license done for much less, in a more condensed amount of time rather than blowing money on flight training/time building with the added expense of a CFI that takes money out of your flight funds you could spend on your instrument, multi-engine or whatever. That extra $2,185 will cover the cost of a multi-engine rating or most if not all of your instrument rating.
Something to seriously consider, especially if you do not have very rich parents who are willing to spend thousands and thousands of dollars for you to do this.
Read this section about the different certificates & ratings plus costs:
If you want to get into aviation but don't have the money or a job at 15, you should consider joining the Civil Air Patrol. It will undebatably whet your appetite for flight (without pricey lessons) while helping you learn the basics. As a member you can participate in the Cadet Orientation Flight (COF) program designed to introduce youth, under 18 years old, to general aviation through hands-on orientation flights in single engine aircraft and gliders. The program will provide for the reimbursement of up to five powered syllabus rides in addition to the reimbursement of the five glider syllabus rides. National headquarters will provide reimbursement for the aircraft and its reasonable ferrying costs at the published CAPR 173-3 rates. Cadets may, at the orientation pilots discretion, operate the controls at any time after the orientation pilot has successfully demonstrated the procedures.
Here is an Acrobat file that details The Cadet Flight Syllabus
Civil Air Patrol (CAP) Cadet Program
The Mobile CAP Squadron contact information can be found here