If you havn't wanted to do this as a burning desire since you were a young'un, or first saw an ag-pilot at work, and if you're not off the land, or at least a bit agriculturally oriented, and if you haven't been working as a mixer or loader driver for an ag operator,.....forget it, you will last 2 minutes before you want to go home.
The best way to get a start is to work in the industry, get your licences and experience, then get a rating and then you may even get a job.
You start right at the pointy end in Ag, the work is exacting and the hours are long, and the boss is not inclined to hand out 1-2 million buck planes to sprogs so expect to start in a dunger and prove that you can get through a couple of seasons doing the hard yards before you get a really good seat.
maybe you should go to the annual AAAA convention, register and sit in on some sessions, drink a few (million) beers and have a good hard look at what you are going to turn out like after 20 years, that alone might just put you off. don't get me wrong these guys really are the best of the best when it comes to actual pure flying skill, if aviation was the olympics these guys are the gold medallists and record holders, but you may not be for their world.
Talk to lots of people about this, it is not a job that you just 'give go and see', yiou need real committment and a certain amount of natural ability of course.