I am glad you found this of service, and so good to see you active on Hive again. I need to drop by your blog to see what's new. Staying under 14MB is key to a successful upload. I'm still a newbie at video editing, but I find Shotcut is user-friendly enough to start from scratch, but has plenty of features that will take a long time to learn how to use effectively.
If your computer is on its last legs, I definitely suggest you experiment with Giphy instead.