I would say in my opinion that any job is a good first time job if you can land the job.
Jobs are getting harder to get so if you're able to get the job at the gas station then I would say yes it's a good first job.
Once you work at the gas station for awhile you can start looking for other work that you might find later.
The gas station job will also give you work experience that you can put on your resume for other jobs and you can use the gas station job as a reference for the other job.