Q: I'm in my 40s and have been taking ballet for four years. How much turnout can I expect? I am flexible enough to touch the floor with my legs straight.
A: Turnout has less to do with age and more to do with your anatomical structure. If your bone structure is in the normal range, you will test with 45 degrees of turnout and 45 degrees of turn-in at each hip. There are people who have more turnout than turn-in and vice versa, but they are not the norm.
At any age, you want to maximize your ability to use your turnout by creating balance at the hip joint. This means you should strive to be flexible as well as strong. Doing ballwork against the wall or on the floor can be useful for decreasing tension in those deep rotator muscles, but remember to stretch them after to release any excessive tension. Working correctly at the barre will strengthen your turnout muscles, but you could include some focused strengtheners, such as the clamshell exercise to target the turnout muscles.
The ultimate challenge is using your rotation on both the gesture and the standing leg. I see many dancers focusing on turning out the gesture leg and losing their rotation on the standing leg. Start standing in first position and slowly lift one foot to coupé, and maintain even rotation at both hips. Balance for a minute and see how the rotators feel (it isn't unusual to have some fatigue on the standing leg side). Then work on maintaining the turnout on the standing leg while slowly turning the gesture leg in and out.