Is it possible to determine whether virginity has been lost in the presence of touching and kissing without intercourse, taking into account that these events occurred at an early age (13 years)?

You must increase your acts of repentance and good deeds, and resolve not to return to such forbidden acts. It is forbidden to reveal Allah’s covering, as the Prophet, peace and blessings be upon him, said: "O people: It is time for you to desist from Allah's boundaries. Whoever commits any of these abominations, let him conceal it with Allah's covering."

It is not obligatory to inform the suitor about the loss of virginity, unless he stipulates it. In that case, you inform him that you are not a virgin, and make him believe that the reason for this was a sudden jump, or repeated menstruation, or riding on something sharp.