Do I really need to pull one of my bottom teeth? (Photo)

I am 50. Never had braces. The older I get the more crowded my bottom teeth get. I was thinking Invisalign - hoped I could just do bottom teeth but apparently both top & bottom must be treated(?). Also the doc I saw said he would definitely want me to have one of my front bottom teeth pulled before starting Invisalign or regular braves (the one that's most out of wack) but I really don't like that idea. Appreciate your thoughts ...