Woman making her salaah qadha due to delaying in checking if her haidh started

I prayed zuhr after it had ended because I'm due to begin my period and earlier when I checked my discharge, it seemed somewhat dark but I still wasn't sure. So I kept checking until before asr. However, I delayed it too long and checked only a few minutes before asr was due to start before I decided I felt more inclined towards me not having started my menses as my discharge appeared repeatedly clear. I ended up doing wudu and praying zuhr after asr began (without doing ghusl). Am I sinful?