Dude, this is a bitcoin forum full of people who are so bullish on btc (and desperate for it), that you're not going to get any answers that are useful. Everybody is going to tell you yes, including myself. I think despite it being at its ATH, it's still worth buying, because the bull market isn't done by a long shot. We'll probably go to $20k or higher by the end of 2018. Don't come back and blame me if it doesn't, though. It's risky as hell but it's made a lot of folks very rich.
Right! All anyone will ever tell is to buy anytime you have the funds. We all did that anyway and there is no point looking back to regret even if things do not end up as one really wished it to be. Bitcoin is volatile, we are still in the early phase and we still have a lot of time ahead of us to grow bigger, so for someone who is going to be holding for a long term, buying now is the best option.
No one would know or really tell anyone what can happen next with the value of these two coins, but as long as we are holding for long, then you can buy now and forget about other things that would happen afterwards.
A lot of people have been expecting that there would be some huge correction and the truth is that so far it has not come and we all do not know when that would happen or if it will ever happen at all. My say would be for you to buy now and if you have more when it dips, then buy more.