saying that BTC may reach to even $17k!!!
Do you think this is possible?
Yes.
From $10k - $15k, very possible. But wait and see as there will be some bit of drops coming its way.
since BTC is not remained too much, some people say it may even reach $100k!!
in this manner, do you think it is worth the risk to buy bitcoin? 
Yes too.
Only time will tell when it will reach $100k. If it's not worth to take a risk and buy bitcoin, we won't be staying hodling it until now. But as you see, holders always win and panic sellers and holders that don't have much patience always sells at any price.