Chicken in the City

Hello. I recently adopted a Rhode Island Red chicken who is approximately 8-10 weeks old, female. We live in the suburbs with a fenced in 40' x 25' yard with low deck. We let her have the run of the yard and she hides under the deck when out alone. She has access to a cage with food and water. We do not currently let her out at night alone. She stays in the house, safe from predators. Is this healthy for her for now until she is a little older and we get a bigger and more secure cage/pen for her? Do chickens do well by themselves? Right now she enjoys hanging out with us when we are in the yard, she helps me with weeding my garden. We currently have no other pets. We have never had any problems with any animals in the yard other than a rabbit now and then. When will she start laying eggs? I would appreciate any tips or advise. Having a chicken so far has been great and she seems to like hanging out with us but does not like to be touched and she runs from us if we reach for her but settles once she is in your hand. I just don't want her to be lonely and if need be, we can take her back to the farm when she is big enough to handle herself against the grown hens. Oh, how big does a female RIR grow to be?