JQuery on click animation not animating

Question

Problem

So, I have a h2 and inside the h2 there is a i and when you click on the h2 , the .inputs underneath the h2 slideToggle() 's. My problem is that when the h2 is clicked on, I want the i to rotate 90deg .

HTML

<h2 class="toggle-inputs">Add Student <i class="fa fa-caret-down" aria-hidden="true"></i></h2>

                <form class="inputs" action="server/add/add-student.php" method="post">
                    <input type="text" name="student-id" placeholder="* Student ID...">
                    <input type="text" name="firstname" placeholder="* Firstname...">
                    <input type="text" name="lastname" placeholder="* Lastname...">
                    <input type="text" name="teacher-firstname" placeholder="* Teacher's Firstname...">
                    <input type="text" name="teacher-lastname" placeholder="* Teacher's Lastname...">
                    <span class="spare">Spare Block<input type="checkbox" name="spare"></span>

                    <button type="submit" name="add-student"><i class="fa fa-plus-circle" aria-hidden="true"></i> Add Student</button>
                </form>

JavaScript

// MAIN
function main() {
    $(".toggle-inputs").on("click", toggleInputs);
}

// TOGGLE INPUTS
function toggleInputs() {
    $(this).parent().find('.inputs').slideToggle("slow", function() {
        $(this).children('i').animate({
            "transform": "rotate(90deg)",
        });
    });
}

// LOAD
$(document).ready(main);

Answer 1

You are using Font Awesome. Wouldn't it be easier to simply change the class from fa-caret-down to fa-caret-left/fa-caret-right as required