Yes, you can. The CLAT does not have an age limit.
The reason age limit is removed as an entry barrier is because the legal field needs people from diverse backgrounds.
You are welcome to attempt the CLAT exam and on securing the cut-off, participate in the counselling for seat allotment in NLUs.
As a 30yr old here are some things you may want to consider before taking the plunge.
1) 5 years of college life - studying, networking and partying hard.
2) You may probably end up being senior most in class so the classroom dynamics will be interesting 
3) Financial commitment of 15 -18 lakhs towards law school tuition fees.
4) Be mentally prepared to allow your personal life to take a backseat.
5) Law is an evergreen, recession proof profession which is demanding (long hours and big egos) as well as rewarding (18 to 25 lakh per annum at campus placements with foreign and National Law firms).
If you feel 5 years is a long period of time, you may want to consider a 3 yr law degree meant for graduates.
If yes, we only recommend IIT Kharagpur's 3 yr law program at
Rajiv Gandhi School of Intellectual Property Law for graduates.
Eligibility for Admission to LL.B. (Hons) Degree in Intellectual Property Rights
First Class Bachelors Degree in Engineering / Technology / Medicine or equivalent.
OR
First Class Masters Degree in Science or Pharmacy or equivalent.
OR
First Class MBA Degree with any of the above
Admission is not based on CLAT though, there is a separate Entrance Exam for the same.
Availability of Application forms online 3rd January, 2020
Examination time on 18th April, 2020: 10 AM to 12 PM.