Yes, you can file RTI application for the copy of your Transfer Certificate. All the government schools are government aided and hence, it is a Public Authority under section 2(h) of RTI Act, 2005. You can file the RTI application to Principal/ PIO of school mentioning your Name, Roll number, Registration number and year of Passing u/s 2(f), 2(j) and 6 with the payment of requisite fees as per RTI Act, 2005.
To file application for the same please refer: https://onlinerti.com/apply