The IRS releases most refunds within 21 days of the date that the IRS accepts the return. (exception: the IRS did not begin processing e-filed returns until 1/29, so if you filed before then, it would be approx. 21 days from that date).
As long as you got the message that your return was accepted, you're fine. Generally you won't see any information on your return on the tracker until it begins to process, which can take some time depending on the volume of returns the IRS has waiting to process. Continue to check the tracker on a daily basis-the information is updated every 24 hours.