Preterm labor & Braxton hicks

Ok ladies, I had preterm labor with my daughter 3 times but never had Braxton hicks. I held her in until 36 weeks. That was 4 years ago. I'm now expecting my second daughter. I'm 20 weeks and 4 days. I've been experiencing a lot of Braxton hicks in the last few days. My questions are "is it normal to have them this early I'm the pregnancy?"  And "is this possibly an indicator to be watching for preterm labor?"