U visa has a huge backlog. Currently it is at 78000 ( on criminal activitied based) with only 10000 visa for the entire U category per year. Please consult a lawyer for finding your realistic chances.

https://www.uscis.gov/sites/default/files/USCIS/Resources/Reports%20and%20Studies/Immigration%20Forms%20Data/Victims/I918u_visastatistics_fy2016_qtr3.pdf