When did BH contractions start for you?

𝓂𝒾𝓁𝓀𝓎 𝓂𝒶𝓂𝒶 • 🌿adelynn 9.14.16 & baby koston 12.31.18🌱
I've been having some super sharp shooting pains that literally feel like my pelvic bone is splitting along with tight crampy feelings in my stomach. The discomfort only lasts for 30 - 40 seconds at a time thankfully. I'll be 16 weeks on Tuesday and I personally feel like that's waaaaay too early to feel Braxton Hicks but another one of my friends is saying it's definitely a possibility. Don't women who experience them much earlier than average experience a more heightened risk of preterm labour within the 20-30 week window? That's what I've been told although I'm obviously not 100% positive about that.