Adding checkbox filters on top of text search box to pagination

Currently I have the following search form to filter pagination result on the blade file:

<form method="get" >
     <input name="search" id="search" type="text">
     <button type="submit">Search</button>
</form>

And the query in the controller:

    $search = $request->input('search');

    $users = User::when($search, function ($query, $search) {
        $query->where('name', 'like', "%$search%")->orWhere('email', 'like', "%$search%");
    })->paginate(15)->withQueryString();

Now I want to add another filter as checkbox, for the example if would be filter for age, so display any result for someone who is "adult", or 18+. This is what I did and it works, however it doesn't seem right:

// added the checkbox
<form method="get" >
    <input name="search" id="search" type="text">
    <input type="checkbox" id="adult" name="adult" value=true>
    <button type="submit">Search</button>
</form>

then added another when to the controller:

    $search = $request->input('search');

    $users = User::when($search, function ($query, $search) {
        $query->where('name', 'like', "%$search%")->orWhere('email', 'like', "%$search%");
    })->when($is_adult, function ($query, $search) {
            $query->where('name', 'like', "%$search%")->orWhere('email', 'like', "%$search%")->where('age', '>', 18);
        })->paginate(15)->withQueryString();

Looks too repetitive but couldn't make it work in another way. And now if I want to add more checkboxes it makes no sense to just copy paste same the same when() lines with the change being the filter itself