At 5'7" you are in proportion to your body. Your photos show a cute compact guy. Why worry? I know a 6'3" 225 lb dude who has less than four. He doesn't worry about it. He is known for his great skills at cunnilingus.
The thing about this post (and nearly all similar posts) is the emphasis on some other techniques. When smaller or even average penises are mentioned, it's like you need to be great at some other technique.
Most here seem to be saying just penetration with smaller or average won't do the job. You have to be good with oral, toys, or some kind of hand clit stimulation. It's the same old thing, only bigger than average will do the job.
There is just no way to escape that reality. I know the posters don't mean it that way, and aren't aware of how it sounds. However, when read into, that's exactly what is says. Not just here, but anywhere in the media, it's the same. When smaller or average is mentioned, there are always ifs, ands, or buts. No wonder so many guys are insecure about their size.
My question is (and I don't know the answer) where does this attitude come from? Is it a sales pitch from those selling enlargement products?
Is it really true that average or smaller isn't good enough? I'm still looking for that answer after 35 years. Not really any closer now than when I started, either.