I am so happy you said that. Hello, "adult capacity equivalent!"
Anything older than that encourages teens not to take responsibility for their own actions.
Oh, brother...OK, I'll bite. What magical positive effect will lowering the age of consent to 15 have on irresponsible teenagers?
Having 18 as age of consent makes no kind of sense, opens up a legal can of worms that shouldn't be (20 yr old dating a 17 yr old, etc).
Yeah...much better to have a can of worms about a 20-year-old dating a 15-year-old.