Not quite sure how you can make that statement since the CRF 150 has only been out for much less time than the TTR. The CRF 150 is a competition race machine where the TTR 125 is more a trail machine that can be raced.
two strokes are probably higher than 4 strokes becuase you were probably looking at race bikes. fourstrokes are usually more trail oriented and designed for beginers. but all of this is changing now.
it's the fourstroke revolution! i ain't happy.
You are slightly off here. The fourstroke revolution has to do with emmisions, the standards set fourth by the EPA are pushing two stroke motors into extinction.
At 14 years of age you are really just beginning to grow. How tall are your mom and dad, brothers, sisters? If you buy a bike to fit you now, you will likely be too small for you in 6 months to a year. The TTR or XR line of bikes make excellent learning bikes and are very capable trail bikes. The newer four stroke MX bikes are performance machines and for some beginners(if not most) maybe too much bike. Ultimately, you have to decide on price, type of riding you plan to do, access to riding areas, your mechanical abilities and your parents limitations. If you buy a performance type machine, you had better expect to work on it regularly. If you have to pay someone to do this work, the cost may prevent you from doing much riding. All bikes need maintenance, performance bikes, two stroke or four, require routine checks and adjustsments for many more parts than you may believe. Failure to do these checks, degrades the machine and its value, thus, making your investment less wise.
I'm 41 and work on my bikes routinely. Some work I have done by professionals but most I do myself. IMO, performance two strokes or four strokes are very fun and can be riden on the trails with small, simple modifications. A trail oriented bike, requires much more to make it a competitive bike for racing but is doable.
Think about how much you will weigh and how tall you will be in a year, then pick a bike that is designed for the type of riding you plan to do.