Released in theaters Sept. 27, Megan Park’s sophomore movie, “My Old Ass,” is about an 18-year-old girl named Elliott (Maisy Stella) who is about to move away from her small town to Toronto for college. A funny script with solid performances, My Old Ass stumbles a bit on the path to delivering its message. But just like Park’s previous work, it’s a movie with a passionate lead seeking answers to their struggles as a teenager.  Elliott is a classic angsty teen character who can’t wait to leave her hometown life behind. She decides to celebrate her 18th birthday by taking mushrooms with her best friends in the woods, which, of course, leads to her coming face-to-face with her older self, played by Aubrey Plaza.