i think its not too late to buy btc today because today is end of the year 2017 is the biggening of the year of bitcoi =n in 2018. so if your are planing to buy now, then its fine just buy more and hold it until will reach to the price that you want to sell it. Good luck to you buddy.
You know about bitcoin months back, and now you are trying to buy then 100% it is too late, but now only you know about bitcoin then you can buy no problem if you wait some more time then it will become again too expensive. $20k we are expected next year, but I think before this year end we can see this price.