Some years it's too early, some years it's just fine. And there isn't a perfect way to predict ;-)

Seed is relatively inexpensive, and I usually have way more than I need, so an early (take a chance planting) is fine in my opinion. If it freezes out, or grows poorly, what's the worst that happens? You just replant. You can try covering things at night with old blankets or a couple of layers of bedsheets. I haven't really done this with new seedlings, usally I am covering things on the other end of the season, to avoid autumn freeze.

The important thing, is keep a journal of this. I simply use a themebook, as I can take it out into the garden to write notes. You may find that your particular yard is warmer or colder than your surrounding area. Mine is a bit colder than what the weather predicts for my area. The fact that my yard sits lower than all the neighbors allows the cold air to settle, it seems. Then again, I have my veggies in the highest area of my yard, and use raised beds, which are geting higher every year, so maybe I'm slowly counter-acting that. What I'm saying here, is there are variances from garden to garden. You might be just perfect for your yard, with your plantings :-)

I hope I'm making sense with this. Anyway, keep lots of notes about your garden in a journal. You will be amazed at what you can learn, by looking back a year or two, and realizing, there might be a trend. Then you investigate a bit. A journal is great winter reading when the plant catalogues come out, too. :-)

Alys, why did you plant your peas in a shady spot? Most do veggies do best in full sun. I'm in zone 5b(zone 6 on the new scale), but more north of you. Our last frost here is usually around mid to late May. They say not to plant the tomato and peppers plants until Memorial Day weekend. I sometimes plant mine earlier, but cover them if there's a frost warning. If starting tomato and pepper plants by seed, most gardeners up here start them in early April.
I wish you luck. But since you're south of me, you just might be ok.

Kat