Well if i were you i would not put all of my money into only one coin. Ethereum will be good you are right but you can make much profit if you put your split your investments in couple of high potential coins.
I think there is no problem in buying etherium with your money as long as you have a purpose in doing it. Also, etherium is one of the most preferred and safest coin that there is since a lot of bounty campaigns utilize it. Therefore, there is nothing wrong in spending all that you have for etherium.