Is it possible to create an animation where I can show a 2 line graphs grow and then end up showing the complete chart?

Yes, This can be done. You need to take the help of the pages in this case and you also have to change the mark type from line to Circle. if you also want to get a longer timeline you need to drag an instance of order date in terms of year and another instance of order date in terms of the month. Also, on the page, you need to click the drop-down and check loop playback. So, it would keep running over and over.