First panels are very hard to straighten. Have you tried cutting your last border the LENGTH of the fabric? I always cut long outside borders this way. Also once it's washed it will be less noticeable. It's too cute of a panel for anyone to notice but you.

See? you did such a lovely applique job, they all think you used a panel,lol! l find that cutting the border fabric on the length of grain ( instead of wof) works best. Then, follow the 'measure center, pin/ease' advice offered earlier. If you take a strip of fabric cut wof,and pull, you will see how much 'give' ther is...take same length strip cut lengthwise...nothing!

Do you stitch in opposite directions? So stitch from the top to the bottom when doing the right side orange border and then bottom to top when doing the blue border. so that each strip is stitch in the opposite direction. Does that make sense?

It looked fantastic as I galloped by!!! Don't stress!!

If I'm making a very precise quilt I fuse feather light interfacing to the borders before sewing to the quilt. Especially narrow ones. A top prize winning quilter at Paducah told me she used misty fuse interfacing on her quilt top and backing before quilting to keep it smooth and square. She said that was normal for show quilts. I don't use it on the quilt tops or backing but it works wonders for my borders.

The center measurement has already been given as the answer to the problem... so I'll just add how adorable I think your quilt is! And I don't see the slightly bent border as detracting in any way from the overall look.

I've had problems with my narrow borders sometimes when they are not cut exactly straight. For me, minor wonkyness seems to be enhanced with a narrow border, (and it's easier to get them wonky when they are narrow). I've had luck doing some easing when attaching the next wider border and then pressing the narrow border flat. Of course, you need to measure the wider border using the width at the center of the quilt.

Your quilt is adorable! Is there a pattern for it?

It's a panel from which I removed the original borders and put my own. Thanks!

Now wait a minute. You removed the borders and put your own on. How did you do that? The trees, birds and rhino overlap the borders. As to the corners--I suppose as someone else mentioned, cutting those strips on the length might be one good solution. I cut mine on the cross and they do the same as yours. I think, too, the quilting makes a difference. Don't fret over it, it's not noticeable unless it's going to be a wall hanging and time will take care of it. This is adorable!