I have a series with most characters appearing in every book. I have been tracking all character info in excel, but the age tracking is becoming too complicated so I'm seeking software that can replace my excel spreadsheets. The feature I would most appreciate is that I can date the timeframe of the book and then the ages will automatically populate. Thank you for any suggestions.
You can use a formula to do that in excel, though it isn't the most straightforward formula.
If you're willing to pay, I can suggest Aeon Timeline. You create the events on the timeline (which you can customise to your needs), create a birth event for the characters, assign the characters to the events they participate in (you can further specify if they're active, passive, observers or just mentioned), and the software automatically tells you how old everyone is at any given event.