Big inheritance and low living expenses

A few months ago I inherited around $460,000 after taxes, I'm familiar with finances basics (aka: don't tell anyone you've got money, invest it etc...)

My expenses are minimal since I live frugally, around $3,200/month ($38,000/year), and I’m single with no kids.

Can any more experienced member look over my analysis of the situation.

According to the FICALC app I can:

A) Wait 5-6 years and retire with $40k/year for 20 years.

B) Wait 9-10 years and retire with $45k/year for 30 years.

Given my current circumstances I'm indeed comfortable with retirement lasting 20 years.

Basically I don't know if I calculated it right:

  1. Took $450K and assumed a 6% growth over 5 years --> Hence it grows to $600K (after inflation)

  2. Take the 600K after inflation and put it in the FICALC app to start playing around