How do you know it's time to start solids?

RA1109

I'm EBF and would like to start solids at 6-7 months. Actually I would like to not start them for much longer. I'm not keen on the idea of getting AF (I know not everyone does) because I'm paranoid about losing my supply those weeks like some of my friends did. My LO is 5 months and doesn't seem interested in solids...why and when do I have to start? Is there any reason to not delay longer? How would I know it was time? I've googled and I'm not finding much that is definitive. I'm seeing that some babies need other nutrients sooner and some can EBF till a year. How would I know if my baby needed more nutrients?