Not if the legal age of adulthood is higher than 16. You could write one, but it will certainly not be enforceable. You need an adult to join in and take legal responsibility or nobody in their right mind would sign any such contract. Until you're at the legal age of adulthood, your parents are responsible for anything you do and you can't do it on your own.
This reminds me of where my parents worked. Frank Taylor, aged 16, decided to build two houses, one for his family and the other to sell, went to a bank for a loan to buy the materials, and of course they said no, you can't have one because you're not 21 (the age of legal adulthood at the time). We can't sue you if you don't make the repayments. His uncle, Jack Woodrow, agreed to join in and be a "sleeping partner" in case of anything going legally wrong. Oh OK then, you can have the loan, And he made his first house sale.
Right, Frank knew how to build houses, there was a big demand for housing back then, and the company Taylor Woodrow grew big. And once Frank was 21, thanks uncle, I can do it all on my own now. The company built other things too, including nuclear power stations and most of London Heathrow Airport.
Big oaks from little acorns grow... they did for Frank, and I wouldn't be here without him! My parents met in the head office. And I worked there too in university summer vacations - Dad's department needed an intelligent typist to enter data into a database they were making, the secretaries didn't seem to understand that it's not the same as typing letters, "Clive can do it" and I made some money.
That could be you - but for now, you'll have to be young Frank and get an adult to support you.