5 month still a little early. Try to wait to 6 months. But some taste here and there is okay. For first couple of months try not to do more than 1-2 teaspoon of anything.
Also try the first food for minimum 3 days and not mixed with anything, so you can see if any allergies.
For avacodo purée, just scoops 1-2 table spoon of ripe avacado and mix with 1-2 spoon of breastmilk, into a purée texture and then spoon it near baby mouth and let baby lick. See if baby like the taste. If baby reject, t
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