I kinda feel the reason LL isn't growing up is cos she isn't allowed too.(though I understand the balancing act her parents must keeping up.)

My mind boggles at being at home at 24.
I was out by 15, in My own flat with 2 dogs and the way by 17.
Was I ready. Hell no. Did I learn fast... Your Damn right!
I don't know what to suggest, because I feel your parents are gonna keep finding excuses for you to not cut the apron strings.
Sounds like your doing the right things tho. Stick with it I am sure it will work out.
Is there not a kennels you could volunteer at. Something that you could stick at that proves it's more than just a passing phase?