I've taken the Wonderlic, Rutherford IQ, the test at psychtests.com, and Raven's progressive matrices. My scores were 46/50 (147 IQ?), 155, 147 (although, highest I could ever get was 131 on repeated attempts), and between 128-138.

I don't feel like spending the money on some official IQ test (or the time, frankly), so I'm curious if there's some semi-reliable IQ proxy I can take online or in person so I may know if my goals are intellectually-feasible for me (PhD in Aerospace engineering from CalTech or USC and helping build the first space elevator).