I presume you are talking about tax year 2019, which is the same as calendar year 2019.
If she was in the US for 7 months of 2019, she could be considered a resident (from a tax law standpoint) through the substantial presence test. You may want to look up IRS publication 519 for more details.
If that is the case, and if her income for 2019 was less than $4200, and if you paid for more than half of her total support for the year, she can be your dependent.
There could be complications if she is married, and her husband does not meet some of these requirements.
