It's more that walking is slow. Everything is slow to Barry, so, he does his best not to make a big deal out of it. He knows the world seems to have slowed down after his powers kicked in. A side effect, probably. An annoying one. Because it made social interactions like this difficult.

"I'd probably move too fast for her after a few minutes," there's a sad note in his voice then. "Not that she'd probably mind--but, ice? Not really a good idea with super speed."