Yes, that is your period. In the beginning your hormones are all over the place and it takes a while for your body to even it all out so that your periods are more regular.
I started my period like 10 years ago and it was always 7 days. About 4 years ago, it got lighter, but for the last 3months or so, it's more like a discharge rather than a full flow. I don't even fill a pad in a full day and it's only for a few days then it's off and on. If it continues to stay that way, then I'm sure it's your period.