What are the options for running for congress after being a United states citizen for 8 years at the age of 27?

Such a person would be eligible to run for a seat in the House of Representatives as long as the position is for a Representative of a district within the state in which he/she resides.

To be eligible to be a U. S. Senator, a person must be...

1. at least 30 years of age.
2. a U. S. citizen for at least nine years.
3. an inhabitant of the state which he/she will represent.