FDGRX (the growth company fund the OP is holding) is the only fund I had left in my portfolio from the before times - I rebalanced my portfolio to a 3 fund (total U.S. market stocks/total U.S. market bonds/total U.S. market REIT indexes) after discovering index investing around 4 years ago.
But FDGRX was the one mutual fund I couldn't bring myself to sell since it was performing SO INCREDIBLY WELL and I only had a few thousand invested and I still really liked holding a tech heavy fund even if it was for irrational reasons. I was allowing myself to play with a tiny bit of my portfolio. So I still have less than 1% of FDGRX, and it's fun to see it grow, but I'm not going to hold a significant portion in FIRE.
As amazing as it would have been if I'd just gone heavy into that fund, I don't think I would leave it as a significant portion of my own portfolio at all at this point. I know enough now to know that it would have been a lousy choice for me to have made, but even lousy choices are sometimes insanely lucky.
OP, my advice is that you should be happy about your luck, but don't press it at this point - rebalance while things are still high into a "safer" AA if you plan on retiring in the next year or two.
I consider myself pretty comfortable with high risk/volatility, but having a tech stock being the main portion of my total portfolio just seems... like gambling more than anything. I'm FIREd just under 3 years and no plans of ever earning/working for income ever again, with an AA of roughly 85% stock, 10% bond, (all total market index funds) with 5% cash.
Totally my take on this, but to me, the flaw in your logic (of holding the FDGRX 100% in your portfolio) is that it is a tech heavy stock and is not a broad market fund at all. It is
very narrow, and has a rather high expense ratio to boot. Not sure if you remember what happened when the dot com bubble burst in the 2000s, but being overbalanced in one sector isn't a great game plan in my opinion just based on that (actually that could also be a take-away from the real estate crash of 2007/08). You could still hold 100% stocks, but as a broad market index fund like
Fidelity's Total Market Index (FSTVX)* that would track the market better. The advantage/disadvantage to this is that you would not have the crazy highs/lows that comes about from investing in a narrowly-invested mutual fund.
*Edited to fix the error where I accidentally pasted the Growth fund's ticker instead of the total market one I meant to put there.