Rebellious stepdaughter picks the one act sure to infuriate both her hated stepfather and her over-protective mother: she has sex with her stepbrother. Trouble ensues.
Why one would want to read about the barely coherent feelings and decisions of that teenager is unclear. Hence, I do not recommend The Awkward Age.
Note to the author of a novel awash with physicians: there is no school of medicine at MIT. Plenty of others to choose from in Boston, though!