B.Tech Eligibility

Yes, you are eligible. Diploma holders in the civil or allied stream are eligible to take admission, in the second year of the course. They must have done their diploma after 10th (3 year) with min 50% or after 12th (2 year) and they need to qualify LEET. Various engineering colleges in India also offer direct admission to diploma holders in second year of the course and in reputed institutes, after completing diploma student gets entry in second year of B.Tech through LEET. Some private institutes like BITS Pilani, VIT, LPU University, etc. conduct their separate entrance test. Top colleges are:
DTUBITS
College of Engineering Pune
Lovely Professional University
Hindustan Institute of Engineering Technology Chennai
Vellore Institute of Technology
P.S.G. College of Technology Coimbatore
Madras Institute of Technology Chennai,
SCMS School of Engineering and Technology Cochin
Veermata Jijabai Technological Institute Mumbai
Anna UniversityCollege of Engineering Pune
Jadavpur University

For better career and growth you should go for regular education as it is technical degree and you need to learn a lot of things practically. For Admission in regular course depends upon your JEE Mains score and percentage in 12th and if you want to join IITs then JEE Advance score matters too. Some reputed private universities such as BITS, LPU, VIT, etc. conduct their own entrance exam. 10+2 with PCM (physics, chemistry and mathematics) with min 50%-60% is the basic requirement to take admission in B.Tech civil engineering programme.
Direct Admission- Engineering institutes which offer direct admission have certain criteria for admission. Either they offer admission on the basis of merit in qualifying exam I.e. 10+2 or equivalent or there are some management seats reserved in private engineering colleges. For management quota the fee structure is generally higher than others. Top colleges are:
DTUBITS
College of Engineering Pune
Lovely Professional University
Hindustan Institute of Engineering Technology Chennai, Vellore Institute of Technology
P. S. G. College of Technology Coimbatore
Madras Institute of Technology Chennai, SCMS School of Engineering and Technology Cochin
Veermata Jijabai Technological Institute Mumbai
Anna UniversityCollege of Engineering PuneJadavpur University