decide what kind of agriculture you want to do and check what is time and money requirements and seasonality is. Next step could be doing internship to see what it it feels like. There are many options from wwoofing to more job like situations.

Well and then you are ready to decide. Being small farmer is tough: not a lot of money and a lot of work, but it is rewarding by many means.

I personally decided to be in more play farm: few acres of vineyards, small wine production. It is still professional operation but I don't expect to be making full living off it.