That's actually a good point for you to not be left out on trend. But as a newbie like the OP, it's a good thinking to start by waiting for the DIP of the market for them to own a lot of coins. Maybe it would be good for the OP to wait for the DIP it just the safest way especially that's a huge amount of investment its a big loss. Still if you afford to lose the money risk could lead to two things, win and lose. And you couldn't get either of the two if you don't risk. It would be difficult to ask for someone calls especially its your money if you lose it you can't blame them. Trust your gut and the risk. In the volatile situation of the crypto there's no guarantee you'll succeed.
OP is planning long for his investment. even he plans for a new ATH or ATH to achieve in the future.
when you get the chance to buy, why not now? because he clearly knows how much ATH Bitcoin was in the previous bull season. and now there has been quite a decline. whether waiting is the right choice or not, but for me, when I have the opportunity to buy. never hesitate. it might be different if the plan is short term or trading.
You can buy it whenever you want as long as you have some spare cash. Even if I have a spare, I'll buy it with bitcoin because I don't want to miss the train like in the past because we were waiting for the dip but it turned out it was already the dip and just left us because we hadn't bought. Also, buying right now is a good preparation for next year's halving, so I am hoping for a positive year next year. I just need to work harder so that I can accumulate enough bitcoin.