Now, these are just my thoughts on the matter - not a medical view!
My ds has always loved corn. For the first few months, puree cooked corn with a blender. I read somewhere that babies can't digest the corn husks, so it can give them stomach pains if they eat it whole when they are very young.
I would say zucchini should be cut into matchstick shapes, and steam-cooked, so it's nice and soft.
Not sure about strawberries. the seeds would be a problem...
lucky you, having a wee one that can feed herself. My 13mo has NEVER put anything in his mouth, including toys, so can't feed himself at all!