Not a bad idea, but don't buy bitcoin just for the "next" halving. What makes you think that the price of bitcoin is going to go up because of the halving? Crypto currency prices are unpredictable. Don't invest based on the events. Invest only if you can afford to invest. Invest if you are willing to hold long term and be committed for lets say two or three years. Yes, the price do go up due to up before and during the halving (and because of the hype..), but you shouldn't be risking your money like this. Yeah, you can if you have money that you can afford to lose. Instead, focus on investing some amount of savings that you won't need and keep investing as long as you can. Halving or not, just keep investing.
And what if the price goes even higher than the $30k you mentioned? Wouldn't it be too late to buy? That's why, don't wait for the price to fall or rise. Just invest if you can, sit back and relax.