Yes of course invest in bitcoin or ethereum. Because these are the most advanced coins in the world of crypto-currencies. I believe that now is the most suitable time for investment. They will soon grow up and you can make good money.
Yes you can invest in bitcoin and ethereum now while it is still in their downtime situation, but do not expect high return of profit and maybe up to not getting a profit. Because crypto is facing a hardships now and we do not know when it can really recover.