I'm a bit biased (I absolutely love WordPress) but I would recommend WordPress for the following reasons:

1. With Wordpress there is way more documentation and support than your typical PHP script would have.
2. There are tons of plugins that will allow you to add extra functionality if needed. With your php script you'd probably need to just write that yourself.
3. WordPress includes a full content management system and learning that system will be a useful, long-term skill. Learning to code would also be useful, but if you have no idea where you're starting, getting to the finish line will be a daunting task.

If it were me, I'd go the WordPress route, but as this is an MVP, either would probably work. Hopefully this is helpful. :)