Hello aspirant,

If you have not filled the form you can not give the exam this year . The eligibity criteria only depends on the academic qualifications, domicile or marks required but not on no. Of attempts. You may give the exam after filling form in the year you want to appear. 

You may also get detail  information by clicking in the link below :

https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/articles/gujcet-eligibility-criteria/amp&ved=2ahUKEwjH5Ij4s5DiAhUMsY8KHcDVDeoQFjAAegQIAhAB&usg=AOvVaw0RfCgiyEBORrG0sqobg0O-&ampcf=1

Thank you!!