If you put a dildo inside you, do you lose your virginity?

Depends: This depends on how you define being a virgin. Typically, we would consider a virgin a woman who has never had intercourse with a man, including vaginal penetration. I would consider that masturbation alone, even with a dildo, by our traditional definition of 'virgin' would not constitute losing your virginity.

Social construct: Virginity isn't a physical happening, but rather it's an emotional and psychological event. A lot of women have used tampons prior to ever having sexual intercourse, and i don't think any of them would say they lost their virginity. Using a sex toy may have meaning for you, and thus may feel like a change in sexual status. That's 100% okay. But it might be different for each individual women.