There is still time to join the Summer #lang Party
Building a large language can take time, but have you considered a little language?
You might be able to do a little language in an afternoon or a weekend so there is plenty of time.
For inspiration maybe read Programming pearls: little languages Jon Bentley (CACM, 1986)
To get started you have a choice
And don’t forget to ask for help:
https://racket.discourse.group/c/questions
Discourse (web forum / mailing list) and Discord (chat) are good places to ask.
Best regards
Stephen