I found the concept of rebirth very difficult to understand when i first found Buddhism but what help me enormously was to look at the world around me,the changing seasons and the rebirth taking place in my garden. As we move from winter to spring we can see rebirth everywhere. We have always been here and will always be here our body’s come from our planet and will return there time and time again. Past and future generation are here with us awaiting to take form, to take rebirth.
I hope you find an answer to this difficult question.
Prayers and Blessing