Hi
Its not a REQUIREMENT to get any vaccinations for Tunisia and you won't be refuse entry. A few are recommended (as they are for most countries) such as tetanus, hep a etc. The majority of people are up to date with tetanus anyway and in the unlikely even that something should happen when you're out there its a jab that can be given when you're taken to hospital for treatment. As for Hep A it wonn't be needed unless you are travelling way off the beaten trap (which as its your 1st hol i assume you're not) or have a chronic liver condition.
If youre fit and healthy and just going on a standard package holiday, don't worry about it and have a wonderful, relaxing trip!
FB