Heading into the second trimester

I have found so much conflicting data on when the second trimester actually starts. Is it 13 weeks, 1 day; 13 weeks, 3 days or 14 weeks?

I am 13 weeks today, so I'm going to say that tomorrow I will be in the second trimester. I am so ready. I hate the first trimester, all the worries, the sickness, the fatigue. With my last pregnancy, the second trimester wasn't much better for the sickness, but the fatigue did go away. Since I haven't been sick this time, I'm hoping I'll feel great in the second trimester. I think that's when most women say pregnancy is wonderful. I hated being pregnant the last time, although it was all worth it in the end.

I think I've been feeling the baby move a little. It's not so much kicks as it is flutters. I can't wait to feel the kicks so that "T" and "B" can feel it, too.