I didn't think you could get it, because I thought it was a limited-time offer, but I double-checked and it says "Players who have purchased Minecraft: Java Edition before October 19th, 2018 can get Minecraft for Windows 10 for free by visiting their Mojang account." So, I'm assuming that means if you've purchased the Java Edition before October 19th, then you can still get it. Oct 19 wasn't the date that offer expired, but rather the cutoff date to where new purchases of Java would allow you to also get Bedrock for free.
So I'm pretty sure you could go look at your account now and be able to get it.