Who are these people that are telling you that you are wasting your time? Are they successful people in the business you are dreaming of entering? If not, than I say, don't listen. Life is interesting and in my opinion the only way to really know if a decision is right or wrong is to jump in! No one can answer the right or wrong decision question for you. No one but you, that is.
Are you excited about starting? What does your 'instinct' tell you. Life is always flexible also; if this is not right for you, you will know in a short time. There are no quarantees that we are making the right decisions, so don't be afraid or worried. "Follow in the direction of your dreams...... always....you will find your path." It may not be the path you thought you would take or had planned for...but you will find your way. Listening to the experience of other SUCCESSFUL chefs, etc., is always a good thing. But follow your heart/ instinct and be willing to take the bumps in the road as you travel it.
I've watched my son travel the road from being the kitchen help at summer camp, to culinary school in Boston, to being offered jobs a couple of the best hotels in Boston before even graduating, then moving on and taking some jobs he shouldn't have and suffering through those bumps, but he persevered and is in a place that is 'right ' for him.
Someone wrote a book a while ago called "Do What You Love, and The Money Will Follow!" Heck, you don't have to buy the book, just read the title...every day!