As you got light bleeding and pain after entering his penis into the vagina, it is mostly suggestive of hymen
rupture. It may be partially or completely.
In general, virgin girl's vagina only allows tip of little finger due to presence of hymen. If 2-3 fingers enter easily inside your vagina without applying any force, we can assume that hymen is completely ruptured. Though one pelvic examination by your doctor can confirm the same.