In your zone anything needing 120 days, I would definitely start inside.
In the future you may want to look for vegs/melons with shorter days to harvest. I do for somethings because we have problems with increased insect/disease pressure due to our heat and humidity. Sometimes this can really help give you a better and longer harvest.
Colorful flowers can really help bring in the pollinators too.
Good luck! Happy to help anyway I can.
Most important! Don't give up!
You will learn a lot by just doing.