Mary Jane flats may be mainstream, but Mary Jane sneakers? Now, that’s something a little out of our comfort zone. Here’s the thing: The trainers trend is one that we’ve been seeing all over New York City this season. Everyone from cool ‘It’ girls to fashion professionals to celebrities is donning the look, including Jennifer Lawrence, who just convinced Us to get a pair. The Die My Love actress may be known for wearing Adidas Adilette slides on…