No, most people will not think you are stupid at least I won't . I started building from kits when I was about 9 years old and built my first R/C airplane when I was 13. That was in 1953 and the radio was built in an electronics class at school.

You can meet your budget of about $300 by building a high wing trainer. A Sig LT-40, Eagle etc., a basic 4-6 channel radio (I like Futaba also but there are others) and a bushing type .40-.46 engine.

You will need to join the AMA and a local club, visit more than one if possible, and get an instructor. Do not try to fly alone you will crash!