Length of orgasm

I've read the average length of orgasm for women is about 20 seconds. I'm pretty certain my (clitoral) orgasms last about 3-5 seconds. Who else is feeling a little left out from shorter orgasms? Also, do we know if the 20 seconds includes the final buildup where there's no turning back, or just the release? I tend to think of it as the release so maybe that's why I'm feeling left out?? A little background so we can try to see any correlations: I'm  34 years old, first orgasm (with a partner) was around 23/24 years old, never orgasmed from penetration alone, typically masturbate with a vibrator (about 95% of the time), and typically orgasm with a partner from oral & every once in a blue moon from manual stimulation.