Can I still use CloudFront if I gave my users a direct S3 URL?

Question

My app has a JavaScript file that my users load into their website:

<script src="https://s3.amazonaws.com/[my bucket]/app.js"></script>

This URL is always the same, regardless of the user (nothing dynamic).

I've been giving out the URL in that format (s3.amazonaws.com...).

Now I've decided I want to use CloudFront because the file takes way too long (~.5 seconds) to load. (question 1) Is it too late, now that my users are all including the above script in their page?

Also, (question 2) assuming it is too late and that I need to have all my users update their <script> tag, is it possible to give out a new CloudFront URL to new users while the old users continue to use this s3... URL, and both will be accessing the same file (i.e., I don't need to support 2 separate files in Amazon)?

Answer 1

Question 1: Yes it is too late.

Question 2: Yes it is absolutely possible to have CloudFront serving the file while also leaving the file directly accessible on S3.