That is great way to buy Bitcoin. If you want to invest so first of all it is very important to do it when you have enough money and you are financially stable. Bitcoin can be very expensive so it is very important not to buy it if you are not financially ready. Instead of this think about using DCA method so you can reduce risks of market going up and down and risks of buying at wrong time. With doing this you will get more Bitcoin over time and it is less stressful way to invest than worrying about missing your chance.
You don't wait to invest when you have enough money or financially stable, you build yourself to become financially stable and that won't just happen overnight it takes time with proper plans ( could be years) so waiting to become financially stable( depends on what you define as beingfinancially stable) before investingin Bitcoin is not a good idea, the value won't wait for you to become financially stable..
Hence, DCA method is not reducing any risk and there's no buying at the wrong time ( all entries will proof to be worth it overtime), you can't accurately predict the market ( that's just how it works ) ..instead, it gives you the flexibility of investing in Bitcoin.