She is so cute! The pies in the background are a wonderful touch, and that flower she is holding is so pretty! And I can't say no to that adorable little face!
I'm actually pretty new to Undertale myself. But I will say that even before playing it, I really wanted to get to know Toriel. I always thought she was very pretty, and seems like a person I would love to know!
Also, this may just be me, but Toriel looks younger in this picture. I wouldn't mind, because young Toriel would be super cute, just like this picture!