Tips are taxable as income, regardless of whether or not they are reported to the IRS by your employer. For employers, the limit on reportable tip income is $20.00 per month. As a service station employee it is doubtful that you would receive tips over the limit. Nevertheless, any and all tips are reportable by you, yourself.
The only way to assure fairness is for you to keep a diary of your actual tips. You should then add those tips to your wages when you file your taxes.
Some restaurant workers complain that their employer reports an average tip income for each employee, whether or not a given employ receives that amount of tips. The employees receiving tips below the level reported by the employer are paying too much tax. This would not seem to apply to your situation.