How can I change data dynamically?

I am creating a personal forecast with a networth forecast (goals) and an actual networth (realistic networth) and I used a 24.5% growth rate every month in my goal net worth forecast. But I would like to know how I can automatically change my networth forecast goal if my actual networth is higher already.

Check what I have here: https://docs.google.com/spreadsheets/d/1WyJXEHm2M-QRP6zu1VfHIldd6nWP3EhT1r0WrzOiYC8/edit?usp=sharing

Can someone help me here?