Date_query problems

Since your code returns the posts belonging to 5 years ago, then I assume your problem is in the conditionals, since none of them are run.

The form elements must have a name if you want to get their values in the back-end. Your select lacks a name, and you are trying to get its value by using its ID. You should use it this way instead:

<select class="select-date" name="select-date" id="select-date">
...
</select>

Now you can have access to $_GET['select-date'] on the server.