Hello, I´m 13 and I´m very interested in Bitcoin, because of this I buy BTC. Actually, I've been studying BTC for over a year to invest. Back to the subject, I buy BTC for 9.200 dollars, and I would like to know if you think it´s a good ideia hold btc until it reaches 20.000. Anyway, for now i´m going to wait btc until it reaches in 20.000 for me to sell. What do you think about my opinion? 
You're only 13 and yet you're already doing some investing. Good for you. It is such a delight to know that a 13 year old exhibits an interest in one very complicated investment such as Bitcoin.
Looking at the value you've bought your BTC, it will be really wise to hold it for some time because at this moment, Bitcoin's value is just above the $8K mark. So literally you've already lose some. Another thing, why settle for just the $20K mark? If i may suggest, just hold it for about 10 years from now. Who knows, Bitcoin maybe worth way, way more than just $20K by then.