
Hi Ellie,
Firstly, as she's 3 years old already she may have quite a few behavioural quirks prior to arriving with you - so as far as off-lead activities are concerned I'd avoid that at all costs just now :)
Do you know why she was up for adoption? Have you any background info on her?
Training a puppy through to maturity is an ongoing process and it may be that your girl hasn't had much effort put in by her previous owners so, if that's the case, you really ought to go back to complete basics with her and train slowly, patiently and using treats as a reward for everything she gets right.
Regardless of age, breed, sex, circumstance, NO dog should be off lead without a reliable re-call. If you're not confident or experienced enough to achieve your aims alone, then please try and find a reputable training club where you can get some expert advice.
Good luck, Teri