If you would like to learn flips faster do tumbling because in gymnastic you won't learn them until you get all the skills for vault, beam, and bars for that level. So in tumbling you will have more time to focus on flip, but if you do want to learn beam and vault most gyms have open gym so you can go in and work in whatever you want.
If you want to do beam and vault, then you'll be taking gymnastics. Tumbling is just doing flips on the floor.
Do artistic gymnastics. You will learn somersaults and handsprings as part of gymnastics but you will learn the other apparatus too. Plus if you start in artistic gymnastics and find you aren't enjoying the range of apparatus you can easily transfer to tumbling (which is still a gymnastics discipline btw, along with rhythmic, acrobatic, trampoline, aerobic and team) but it is harder the other way.
GOD. Please do gymnastics. This is coming from someone who did tumbling & trampoline for almost a year. I couldn't stand it! Yeah, gymnastics has tumbling but it's way better than JUST tumbling. I switched to gymnastics recently and I LOVE IT SO SO SO MUCH. do it do it do it!
Tumbling!!!!!! I do tumbling and it is AMAZING!!!! I love it.... But then again I do it for cheerleading I practice cheering and tumbling sepretley..... But tumbling is awesome.