I want to start BMXING but I don't know what's good or bad about the bikes.
I am 13 years old
Height: 5"7
I want a bike not over $400
Here's a few bikes I was kinda interested in. Tell me the pros and cons or if I should or shouldn't get that bike.https://www.jrbicycles.com/storefron...productId=5862
Here's another bike: https://www.danscomp.com/products-BI...Curb_Bike.html
Another: https://www.jrbicycles.com/storefron...productId=5895
Please tell me if these bikes are good or bad and post links of bikes you think would be better for me!

Those bikes are all about equal quality. There are some differences in geometry, which will effect how the bike handles. What type of riding do you plan on doing?

Street riding
Maybe dirt riding

at 5'7" these bikes will be a good fit for you right now (though they are better for a person just a tad shorter), but seeing how you're 13 years old and probably going to be hitting a growth spurt, you'll outgrow the bike really soon. You might want to look into something with a longer top tube.

Do you have any suggestions in bikes?

If you like the Kink Curb, look at the Kink Gap or Gap XL. The Gap is just a tad bigger than the curb, and the Gap XL is a little bigger than that. There are plenty of bikes in your price range with a 20.5-21 inch top tube. No matter what you pick, you'll love it, but at the same time, you'll wonder if you should have gone with something else. It always goes like that.

Go with Sunday Bikes Completes I saw the videos of the pro team riding the completes right out of the box and they will definitely hold up to anything you will throw at it.

Here's the video: Re-Up: 2014 Most Complete Completes « Sunday Bikes « BMX Bikes and Parts