If I read this right, you've already owned an amazon. Because you said 'another' amazon.
As long as you've had the experience, done your homework, are aware of the expenses and time involved; I say go for it!
The nice thing is, she's already 30 years old. So, she probably wont out-live you. I think all you need is the above mentioned preparation, and you'll do just fine. It's also nice to know how she acts around other parrots. I reccomend that you spend more time around her to get an idea of what she's really like before you decide for sure to go ahead with it.
Let us know what you decide!!