Society tells you to work to make yourself more valuable. Then it tells you that when you reason morally, you must assume that all lives are equally valuable.

Nitpicking: I don't think this is a good way of framing the issue. "Society" doesn't tell you to do anything. There are societal structures in place that reward certain actions, but you are not told to do anything one way or another. I only mention this because you are not the first to do so.

As far as your ethics are concerned, you are assuming that a rationalist will be able to deduce the best possible action at the outset of his life, instead of experimenting with various strategies and updating your beliefs. In a probabilistic environment, reward matching is the best strategy.