In such a situation a case for kidnapping can be filed agaisnt you. For the police to charge you for this it has to be proved that you enticed her or forced her to leave her parents or lawful guardians. In the case of S. Varadrajan v. State of Madras it was held that if the girl had consented to being taken away, it would not be considered kidnapping. Hence if the girl had gone with the boy on her own volition by knowing the impacts of her act, you cannot file a FIR for kidnapping. Similarly the The Delhi High Courtin the case of Sunil Kumar v. State of NCT Delhi,( I (2007) DMC786)held that if a 17 year old girl runs away from her parents to be with her lover then it is not offence on the part of either the girl or the boy.
Therefore, the video recording and the statement made by the girl will be enough to prove that you did not force her to leave and she left with you on her own. The video can be submitted as an evidence to help your case but it msut be supported with other evidences or witnesses like statement made by the girl herself.