In a large bowl add the 1 pound uncooked and chopped shrimp and ½ cup fresh lime juice. Let stand for 5 minutes until the shrimp turns opaque, the lime juice will cook the shrimp.
Add the 2 chopped Roma tomatoes, ¼ cup diced red onion, 1 diced jalapeno pepper, and ¼ cup chopped cilantro, and toss with the shrimp and lime juice. Cover and refrigerate for an hour.
Add the 3 diced avocadoss and toss right before serving and salt and pepper to taste.