I drew a path with the pen tool, thinking the path would begin at the start of the first point I drew. However, for some reason when I animate a stroke on that path, it starts at around the 3rd point that I drew, so when I start animating the stroke using the start/end commands it starts drawing it at the wrong spot. Select the mask vertex you want to be the starting point and select 'make first vertex' from the dropdown menus at the top of the program window ... I don't recall off-hand which one its in, but it should be pretty easy to find. It looks like it's grayed out because I don't just have one point selected, but how the heck do I select just one point? If I click on one it highlights the entire path. In the comp window, you should just need to click off the mask once to deselect it, then simply click the vertex you want to select ... I'm still on CS3 so I hope Adobe hasn't made such a simple thing more complicated in CS4. For whatever reason, every time I was clicking on one vertex (even after deselecting them all) it was selecting everything. I just restarted the program and then I was able to pick one at a time. wow, i had been trying some silly work around on my last project for exactly this issue. thanks for bringing this to light. i wonder why the first pen point isn't set as the first vertex by default? seems like that would be a bit more intuitive. Source.