Is it irresponsible to tell a young child he or she can be anything he or she desires once grown up?

It is really hard to answer that.

My daughter recently told me she wants to be an actress....I told her she can be but I also told her how many out of work actors there are, and how she must keep focussing on body image and the truths of casting couches and money. I told her she has so many other talents and that she must have a back up plan