js动画效果有bug,帮我看下

bug就是点击第一次不会有动画效果,第二次以后动画效果正常.
html结构如下

 <div id="eventContainer">
                            <ol class="eventNo">
                                <li class="active">1</li>
                                <li>2</li>
                                <li>3</li>
                            </ol>
                            <div id="eventDiv">
                                <div class="eventPic">
                                    <img src="statics/images/event.gif" alt="">
                                    <div class="eventTitle"><a href="">[商会]聚焦公益人文关怀...</a></div>
                                </div>
                                <div class="eventPic">
                                    <img src="statics/images/event.gif" alt="">
                                    <div class="eventTitle">活动2</div>
                                </div>
                                <div class="eventPic">
                                    <img src="statics/images/event.gif" alt="">
                                    <div class="eventTitle">活动3</div>
                                </div>
                            </div>
                        </div>

js代码如下:

 $("#eventContainer .eventNo").find("li").each(function(){
    $(this).click(function(){
        $(this).addClass("active");
        $(this).siblings().removeClass("active");
        var $pic=$(".eventPic");
        $($pic[$(this).text()-1]).slideDown("slow");
        $($pic[$(this).text()-1]).siblings().hide();
    });
});