It depends on the type of visa you have. For example, if you are on student visa, your days of presence do not begin to "count" until after you have been in the U.S. for a part of 5 calendar years.
See the section of IRS Publication 519 at this link for information on the Substantial Presence test. Note that your type of visa may make you an "Exempt Individual" for a certain period of time, and your days of presence do not count while you are an exempt individual.