Since your female is only 3 years old, I would recommend that you don't try to purposely double clutch her this year. This is her first time and you don't want to stress her too much. There is always exceptions, however. If she only lays a small clutch and/or has alot of infertile eggs (slugs), and still looks in excellent condition, you could probably double clutch her. If she lays a large clutch and/or loses alot of weight/condition, don't double clutch her. She may go ahead and lay a second clutch anyway, and some eggs may even be fertile without the male having bred her again. Just make sure she gets lots of TLC after she lays, and even more if she has a second clutch. I've had several first-time females that had trouble putting weight back on after they laid a second clutch when I didn't want them to. I had to totally remove them from breeding for the next year just to get them back into condition.