Thank you for writing in Yourdost. As I can see that you are going through a dilemma, I would like to clarify that no one can predict the chances of success in a love proposal or even in a relationship. It is appreciable that you decided to express your feelings to this girl and be true to yourself, but we cannot force someone to be in or out of a relationship. It happens naturally. As much as it hurts, but sadly, that is the truth of life.
As for the video, it is up to you to decide when you can give it to her, as you are the one who is completely aware of your life situations currently and when will be the most appropriate/convenient time for you and her as well.
You have mentioned that your final year will get completed on 21st May 2019. I wish you all the best for your future endeavors and success in life.