only double down a lot if you never carry positions very long- ie have a somewhat close stop. everyone always says doubling down on losers is bad, but from my experience it is nothing but free money- but i never have had a horrendous loser due to doubling down too much on a losing trade because i am 100% cash by close each day.
I would advise you to take some of the money and buy a good backtesting platform and test your ideas first. You will learn a lot, including how hard it is to make money daytrading and how useless common indicators are. You will also learn how to place stops and how they affect profitability. I would strongly urge you to put 3/4 of the money in a separate account, so it is not available for trading. After a few months, if you blow out your original account, you can decide if you want to keep trading.