Peppers are slow-growing as seedlings, and even take a while to germinate. They also love hot weather, and we haven't really had much of that. Tomatoes are more forgiving. Mine are 5 feet tall. You might set your soil tested. Can do that tomorrow at Soil Kitchen.

It's really only the beginning of Spring still. We just got a cold front that dropped temps in the upper 30's/lower 40's this past week so I think your peppers will be fine. They love the heat

Agree with the others. It's because we're not into the full growing season/weather yet. But rest assured they are making roots, so keep helping them along.