Welcome to DRN! If you use the search function, you will find lots of posts with recommended gear, and different opinions of the order of importance. For just getting started, a helmet and boots are a must. Other things to consider are a chest protector, knee pads/braces, gloves, goggles, neck protection, pants, jersey, kidney belts, elbow pads. You can find tons of used gear online for very reasonable prices, if you're not ready to buy new.
As for places to ride, if you decide to try MX, Bithlo is a nice track, and should be pretty close to you (its on highway 50 on the east side of Orlando). They are open for practice 6 days a week, including night practice too. The back track is usually open for riding the whole practice. It's sandy, and there aren't many jumps, but it is good practice. The lighted part of the track is more supercross style with more jumps and whoops, and they rotate every 15-20 minutes based on skill, so you can ride with other beginners. You can also loop together the back track and lighted track for one big lap.
Other tracks within an hour are so of Orlando are Bartow, Pax Traxx (Bunnell), Dade City, Hard Rock (Ocala), Sunshine (Clearwater), Ace (Sanford). Hard Rock is a great place for beginners, as it's 100 acres with several different tracks, plus trails. Although the dirt is very hard packed, compared to most of the other tracks in your area which are pretty sandy/soft.
Links:
http://www.bithlomotorsports.com/
http://www.bartowmotocross.com/
http://www.paxtraxmx.com/
http://www.dadecitymx.com/
http://www.hardrockmx.com/
http://www.sunshinemotocross.com/
http://www.acemotoxpark.com/