By Pew’s definition, a three-person household was middle class in 2014 if its annual income fell between just under $42,000 and about $125,000 before taxes. 

Costs break down
Taxes= Based on household Probably around 15%-25% based on dependents maybe less. 
Retirement contribution typically 4% (most employers match up to 4%)
Housing= $16,752 a year.Two-bedrooms carry an average rent of $1,396, which is $192 more expensive than the national average for a two-bedroom apartment. For a three-bedroom apartment you can expect to pay around the Colorado average rent of $1,744.  
Health Insurance= $10,000 for HDHP So remember additional costs for copay's based on Kaiser data. 
Food=  $5400 a year (Based on $150 a person per month*3)
90% of Average households report spending $3,000 a year on gas
Education= Denver Academy 2007- Because I went to school there= $22,000

I guess if you are making the upper end you might have a shot at affording Kent or Denver Academy but its not looking great.