Relax Jackie.You have adopted a right hobby. sure you will become more patient with orchids. Coming to your question on maturity, there are many species that range from a small size (C.walkeriana) to large (C.maxima, C.amthestoglossa) and hence it is quite difficult to ascertain by looking at the size. you might want to look at the parentage of the hybrid to cross verify the maturity.
secondly, flowering and maturity is bit different in my opinion, you could have a mature cattleya but not flowering and a small sized cattleya flowering. this is largely controlled by the cultural and environmental aspects of growing (light, humidity, day length).
name of the hybrid and posting a picture might help