I have 13$ worth of btc.i dont understand what will happen,if i holding this btc for a long time ?
It just depends on how long you hold and what the price is when you sell or trade for goods.
It could be worth $1 or it could be worth $10000
It could be good to hold your bitcoins for a long term, keep in mind there are more risks that you have to take to do this but it will also maybe be more profitable at the end, A long term investment can let you gain a lot of money if the bitcoin grows to a very large currency.
I think there is no any risk to hold our bitcoins for longer as if we have a good knowledge about bitcoin and keep a bare look on its price and other events and get a good knowledge about trade then it is not possible that we will lose anything with our bitcoins. I have my bitcoins in my wallet from about more than 8 months and I have not lost any amount in there in that period, which is a proof for me that there is no any risk to hold for longer.