When does it start?

Ali • Full-time student working on my RN-BSN while expecting baby number 1! Due July 2016! ❤️
I have NO idea what to put as my start date for my period. Reason being, for about a week or so before it "really starts", I'll bleed every other day or so, and some days I'll have pms symptoms, others I won't. 
​It's very frustrating seeing as how it makes me feel as if I'm on my period for two weeks.  
​My question being- for others whose cycles may be this way- how do you track your periods and ovulation? I'm not actively trying to conceive (hopeful to start actively trying within the next year) but I don't want to bother getting on birth control when I've never been on it and my partner and I both have a "If it happens, it happens and we'll be glad" mentality.  
​I'm sure this seemed a little jumbled- just looking for input. Wondering how to track and if when the time comes, it will be harder for me to conceive (we have had sex during what Glow says is my fertile window and I haven't gotten pregnant).