C++ loop because of text in an integer

Question

Im new to c++, right now Im doing a small app that helps me to understand and develop knowledge about it, however Ive got an unwanted loop. When I input a letter instead of a number its being picked out and recognized as an error - because it is an integer, however I need the script to go back and ask for a correct value, which makes me go into a loop which Im not able to get through. Any advises and help appreciated, Thanks

Code:

#include <iostream>
#include <time.h>
#include <conio.h>
using namespace std;
int age;
string namevar;

int born(int age){
    time_t theTime = time(NULL);
    struct tm *aTime = localtime(&theTime);
    int year = aTime->tm_year + 1900;
    cout <<"Current year is " << year << endl;
    int cage;
    cage=year-age-1;
    cout << "Born in " << cage << endl;
}
void namefun(string namevar){
    cout << "Your name is " << namevar << " there is no reason behind this comment\n you may leave now." << endl;
    }

void yes(){
    cout << "You are 18+\n";
    }

void no (){
    cout << "You are less than 18" << endl;
    }

int main(){
    cout << "Hello, enter your age bruh" << endl;
    cin >> age;
    if (cin.fail()) {
        cout << "Make sure to input a number only" <<endl;
        main();
    };
    if (age >= 0 & age <120){
            cout << "You are " << age << " years old\n\n";
            if (age >= 18){
                yes();}
            else{
                no();}}
    else{
        cout << "sorry invalid input"<< endl;
        main();};

        born(age);
        cout << "Please enter your name for no reason!\n";
        cin >> namevar;
        namefun(namevar);
        getch();
        return 0;
}