also know that obviously there is a risk in this investment and if you invest $3000 in bitcoin or anything else it may turn into 0 by 2019. the reason can simply be you lost your wallet!
Bitcoin and ETH I suggest. If there are any coins that can possibly grow and survive for years it would be the two of them.
i don't know about ETH is long term but there are a lot of coins that can be very profitable in short term including ETH but in order to successfully pull out a good amount of profit from them you need to be very familiar with the altcoin market and be a trader. and i don't know OP and his rank is low so with the assumption that he is new my suggestion is something that has the least risk.