This is one thing that bothers me about Android vs iOS. You can record a video with an iPhone and then send it in a text with no problems. (the video quality is absolutely horrendous because it is downsized, but at least you're able to send) With Android, if you record the video in a high resolution ( which everyone does), you are not allowed to send it anymore without having to use some 3rd party solution; whatsapp, video trimmer, etc.
The 2 ways around this are to change the resolution to limit for MMS (which sucks because your video is gonna look like hot garbage) or choose capture video straight from the message.