Buying it now is fairly reasonable. Though, I wouldn't be surprised to see it crash yet again, even harder, but it felt like buying on that upswing to 20k was suicide.
I'd wait few months. If it is actually crashing not just backing up before next silly raise then you'd be better off waiting till it settles after the crash. It usually takes few months or a year.
If you don't want to gamble, bitcoin is rather long term investment.
Anyway I invested the $100 and I am down, but whatever it's like going to the casino and gambling/losing it all.
In 2011 (or something, I'm going by memory) it rose to $30 before crashing back to about $5. In 2013 (still the days when all people had to do was spam a few forums) it reached $10, $100, $200 before stagnating until MtGox and Willybot pumped it up to $1k.
ISTR some people back then were predicting $10k BTC by the end of the next year (end of 2014). Instead it was about $500 or something, and BTC didn't reach $1k again for about three years (the start of this year or end of last year).