Adorable pattern!
Very cute pj set purchased for my daughter who will be turning 2 soon! I ordered her the 18-24 month size in the two piece set and it fit her great with some wiggle room. She’s a lean kid so I went based off of our known experience with little sleepies running big and this set fit her well! I also purchased a 2T two piece in a different pattern to compare the two sizes and there wasn’t a huge difference so depending on your kid’s size, either one could work.