In my opinion at least, I don’t think age has a whole lot to do with your investments—it’s more about your time horizon to retirement.
What I mean by that is if you’re 30 years old and want to retire at 40, your investment strategy isn’t necessarily different than if you’re 50 and want to retire at 60.
Now, SSA and medicare could throw a wrench in things but that’s a different topic.
So far as retiring in 12-15 years, you need only achieve perfectly average returns that mirror the S&P 500 (or the total US stock market such as VTSAX or VTI for example) to do so along with your seemingly healthy investment level (40-50k).
But most importantly, will that support the spending you desire in retirement? That’s the key question.
I’d recommend checking out this calculator and plugging in your numbers to see how it comes out:
That calculator is a great tool to play with.
We write a lot about early retirement (with somewhere around a 10 year time horizon) and general consensus is to aim to have 25x your desired spending, invested, to retire and live off the proceeds. Those investments tend to be in well-diversified index funds.