First impression was, this is pretty good! Second impression after I read you did this with a mouse, this is pretty GREAT. Trust me, I know the drastic difference between drawing with a tablet and mouse, and its a pretty severe handicap. Your linework and coloring is fantastic considering that, you have great detail in the grass and the lighting on the edges of the characters clothes is well done. There are minor things that could be improved, but I won't even mention them because I'd venture to assume they'd be fixed if you had a tablet to work with anyway! GET A TABLET GODDAMIT! You've got a lot of potential here! Thanks for sharing :)

YOU SHOULD HAVE PUT HAPPY VALENTINES DAY, DAMNIT! xD
Great picture though, man!