Hello, this is Dr K.. Answers are not medical advice and do not constitute a doctor/patient relationship. I look forward to helping you today.
Yes she could be pregnant if she ovulated late and conceived in early March
She is not pregnant if she ovulated on time.
A home pregnancy test will be positive as early as 10 days after unprotected sex. It will always be positive 2 weeks after unprotected sex, if you are pregnant
That does not mean she is pregnant if the test is negative