How much food should I let baby eat when starting solids

I've just started introducing solids to my 5 month old son. I've just started baby porridge once in the morning and will start introducing pureed vegetables in a few days. How much can I let baby eat? Day 1 I made 1oz and he didn't really eat it. Day 2 I made 1oz and he ate it all. Today I made 3oz and he ate it all and wanted more. I use the formula scoop to measure 3oz then add the water. Can I give too much?

Update: I know I have said weaning I didn't mean weaning from milk more just introducing solids. I have used wrong wording. I know milk is main source of nutrician until a year and he's still having 5 bottles a day. I was asking the question cause I'm wondering do I let him eat as much as he wants (if offering 3oz) or should I limit what I offer. I gave the porridge 1.5 hours after his morning bottle.