You'll be fine.
Assuming your wife\partner will be getting a work visa through her job, you will be able to apply for a work visa as her partner - its very straightforward, when she fills out her application forms she lists you as her husband (or partner if you're not married at that stage). You may have to provide proof of your relationship i.e. if married, the marriage cert and if not married proof that you've been in a relationship ( bills in both your names etc).
the age thing only matters if you're applying for australian residency - its a points system and you get less points as you get older (there's a 5 point difference between under-30's and 30-35 year olds). This doesn't seem to apply to your situation as it appears to be a work transfer.