Is 2.5 gigabytes and 500 megabytes enough?

[dollie]

Well I'm a teenager so of course I'm going to use the phone a lot. I use the internet a lot and FaceTime a lot. I take pictures too. Im also starting to like watching videos a lot. ( I can stop doing that though if it's going to take my megabytes away or whatever they're called )
My moms going to put me in the family plan with my dad and brother ( we switched to tmobile ). I'm trading in my aunts iPhone 4S for the new iphone 5c. I have unlimited call,texting,web but I have 500 mg and 2.5 gb. I don't know if that's good enough for me. I use the phone a lot and I don't want to overuse the new phone my moms getting me because I don't want her to pay a lot because I wasted all my mg.
I tried researching all this but everyone's saying different things. Please help me (: thank you! I'm not good at this.
Also, if I use wii, will it still take away my megabytes or gigabytes? Like if I'm at home using my phone with wifi will it take away mg or gb ? Is cellular data the same as wifi?