The price doesn't seem too bad to me (but the prices in Canada are higher than those in the US, so my opinion may be skewed a bit...).

She will more than likely keep her dark colour into adulthood. She may go through some minor changes, but nothing drastic.

As was said above, whether she passes on her dark colours to her offspring is anybody's guess. It may be a genetically inheritable trait, or it may not be. The only way to have a definite answer is to breed her.