Coming from Hawai’i, at sea level, anxious about altitude

I’ll be visiting for 2 weeks coming from coastal Hawaii, so right at sea level. I’m really anxious about altitude and keep reading about worst case scenarios (HACE and HAPE). Are these real risks? I know drinking water and taking it easy/avoiding alcohol help, but is there actual reason to worry or am I overthinking it?

I plan to spend the first 12 hours or so in Denver before going up the mountain.