sliders from what i have read generally males mature at 4 years (possible 3 im sure loco) females tend to take till about age 6 to become mature mating effort will take place on the males side as he matures younger but dont really get too excited unless you know your female is of age to become mature (i beleive females will average around 6.5-7 inch shell range to become sexually mature)
i havent owned stinkpots (yet im currently looking into them as i want to get a breeding pair...possible trio) but take vicous's info on that one his turtles are always good and healthy...