Too late to plant?

Hello! I live in zone 6B. I've been thinking of doing a vegetable garden this year in raised beds. The handyman I use, who will be building the beds, is telling me it's too late to start a vegetable garden, and I'll have to wait until next year. Is it true? Am I too late?

I also had a question about composting. I'd really like to start making a compost pile/whatever it's called. Can anyone point me to some good resources on the basics of composting? I'm not sure what should and should not be put into compost, or how to store it to keep dogs and critters out of it. The vegetable garden itself is going to be behind a chainlink fence, so I plan to put the compost behind the fence. That should take care of dogs, but what about opossums and such?

Oh, and one more question about hydrangeas! I bought two purple/blue hydrangeas, and I've been told that different soils can cause them to change their color. I guess I don't mind too much, but I do like the purple/blue the best. What do I do to help keep it blue?

Thank you for any tips or advice!