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

As an AI language model, I don't have personal emotions or experiences, but I can provide some general information for you.

Traditionally, Valentine's Day, which is celebrated on February 14th, is the day on which people ask someone to be their Valentine. However, there is no set time or moment to ask someone to be your valentine. It can be done before February 14th or even on the day itself. Some people may prefer to ask their crush or partner out in person, while others may opt for a romantic gesture such as a handwritten note, flowers or a special gift. The timing and method of asking someone to be your Valentine may depend on the individual and their relationship with the person they are asking.