It's my understanding that it's too late right now to start seeds for tomatoes, peppers, and eggplants (something about the needed nighttime temperature when they are flowering), but I think everything else you can start from seed right now, you just need to get plants of those three (the food co-op is selling organic heirloom tomato starts).
the food bank has a good calendar
. they also have a cool home gardening program where volunteers will help you put in a garden, and they have compost/seedlings/shade cloth at their demonstration garden-- I think the shade cloth costs money but the other stuff is free.
All of our gardening space is taken up with our winter garden right now, so we need to clear some space for summer plants!!
And in terms of gardening with a toddler, my rec from the last 2 years is to accept that some plants will be damaged, eaten early, etc., but that it's a fine price to pay for getting your little one accustomed to taking care of the garden. After 2 years of gardening, Carter is now very gentle and an expert seed-planter and waterer!