I just noticed that you are 15 yrs old and not to knock you because of your age, because I started playing seriously when I was just a couple of years older than you, but I do have some advise for you. Nobody needs 100 watts. For what you'd pay for a solid state Marshall stack of that wattage, you could pick up a tube amp that will give you 100% better tone. Whether you want a head/cab(s) set up or a combo is up to you. Keep in mind that tube wattage is probably twice as loud as solid state wattage. Technically, it shouldn't matter from an electronic standpoint, but the fact of the matter is that it's true.
Again, not to use the age card or toot my own horn, but I started playing professionally, full time more than 10 years before you were born...so I do know what I'm talking about.
Where were you planning on playing with that much volume? These days if you crank up a 100 watt amp in anything smaller than a football stadium, you would probably get your ass fired so fast your head would spin. All the acts you see with huge stage rigs are just using those for the show, not the sound. I happened to share the stage with Judas Priest back in the early 80's. Mountains of Marshall cabs on stage. All empty. One of the guitar players (can't remember which one) was using a Fender Deluxe for his stage sound. That's 22 watts BTW.