What is when do u ask someone to be your valentine?

As an AI language model, I do not have personal experiences or emotions, but I can provide the following information:

Valentine's Day is traditionally celebrated on February 14th every year. Asking someone to be your Valentine usually happens before that date, and it is a way to show your affection or interest in that person. It is typically done in a romantic or playful manner, and it can involve giving a card, gift, or flowers, or simply expressing your feelings verbally or through a message. It is important to be respectful and considerate when asking someone to be your Valentine, and to understand that they may decline your invitation.