its rarely been a good idea to wait.
i'd say get some now, and get some later when the price drop, and get more when the price drops, and get even more when the price drops even lower, and buy even more when the price drops lower still
the idea is at one point it will stop dropping and you'll have bought an amount you're comfortable with
plan a price you think bitcoin has a reasonable shot at reaching assuming it crashes really hard after lots of unexpected bad news, so like 400 or 500?
dont assume we're going to have wave after wave of bad news and selling, and wait for that price, it'll never come... just consider it a possibility.
then buy some right now ( cuz you're bullish ) but not to much, enough so if it drops -20% your kinda sad but not stressed ...
price drops -20%? you're still bullish on bitcoin? part of you has been hoping for lower prices? you not stressed! you know what to do!