At 3 months, I think the best thing you can do for her developmentally is to spend some quality time with her. You can hold her (it won't spoil her I swear!), carry her around or in a sling/carrier and just talk and show her things like around your house, board books, etc. Believe it or not, this is probably the most "educational" and bonding thing you can do with her at this point. I would put my son in his bouncey seat in the kitchen and show him what I was making, let him smell things and tell him what I was doing. It seems really lame when you're doing it, but anything that engages multiple senses (touch, smell, hearing, etc) is going to develop the brain far better than any video can (and chances are her vision at this point would prohibit her from actually seeing anything on a tv clearly).
If you're looking for things to help tummy time become more bearable for her, we found some blocks and balls (i think they were Fisher price) that were clear and had things inside them like balls, little animals and other things. My son loved those. The simpler the better (ie no batteries are necessary to keep their attention). Also, keep in mind they have really short attention spans at this point.
Congratulations on your baby! Enjoy her. These days are so short!