Sending video's through Whatsapp?

I'm trying to send a video through to my friend. It's about 40 seconds long. It keeps showing a message saying only the first 16mb of the video will be sent (which seems to be about 15 seconds) as the video is too big. But she was able to send me a minute long video just fine and it didn't warn her it was too big? Why? I did see that Whatsapp has a limit to their videos and you can only send a certain amount, but I saw you can send up to 90 seconds worth. It is anything to do with the phone? She has an Iphone I have Windows Nokia phone.

Its not about the total length of the video its about the amount of data. There's limit on video size and not on time frame. One minute video can vary in size depending on the quality and format of the video. Try sending the same video which you received from one friend to some other friend and check it. I'm pretty sure you can send it successfully.