Make sure you have a verified YouTube account that will allow you to upload more than 15 minutes. https://support.google.com/youtube/answer/171664?hl=en
If the time limit still seems to be a problem, you can use a simple editor like Clipchamp or Adobe Express to remove some of the content.
If the problem is file size, you can download a free app called Handbrake to compress to a smaller file size.
