This sounds like a pretty cute story. Nice job. )
You have a few mistakes, such as writing, "you're" when you meant, "your." Those are pretty common errors and they pass unnoticed for the most part, but you still might want to correct them. Also, some of your sentences were a bit awkward sounding, but otherwise, you did a nice job.
That preview was awesome sounding! Can't wait for updates.

Awww, this was so cute! I love Christmas and I don't think I've seen a Christmas-y fanfiction for Ben 10 before. There were a few grammar mistakes here and there, but other than that, everything is completely fine. V's outfit sounded so cute even if the dress was a little short.
An example of one of the errors: "Hey Ben, good to see you." Max said. There should be a comma instead of a period after the sentence that Max said.
Also, the sneak peak was epic! I can't wait for it to come out.