My pop pop started a construction company in 1976 with only $500. The company now averages between $5 million to $10 million per year in revenue. To the OP, dont let anyone discourage you. Find your niche, pursue it and never give up.
My advice is don't start your own business unless there is something you are passionate about, have a unique angle to the market, has proven commercial viability and you have a spouse who also has a job that earns six figures.