Picture this, you go to the local Karate place and you tell the instructor you want to be a black belt. He tells you to come to class three times a week, and to practice every day. At the end of seven years, you can have a black belt and be like Chuck Norris.
Earning the status of a successful entrepreneur requires that you train just like a karate student is required to train to get a black belt. You have to learn what goes into becoming an entrepreneur just like the karate student learns the skills required to be a black belt.
Entrepreneurs get their education in two separate ways; one is through the school of hard knocks, where the entrepreneur learns from making mistakes when they could have created a plan instead. The other is to take time necessary to build a solid business plan, which few entrepreneurs will do.
The tests come in the real world, and are often unforgiving so perfection is demanded from the instructor. Unlike when you were growing up, the real world tests don't give do-overs and they tend to be very unforgiving. The report card is always being handed out with every move you do.
Even if you have experience in entrepreneurship, you still need to practice to keep your skills current, just as you do in Karate. Can you imagine practicing for seven years, and then taking a break for three years, and testing without any preparation in between time? You probably don't stand a chance at passing your test.
If you really want to become an entrepreneur, it's never too soon to start practicing and getting educated.