I played from the Arban book for years, can I just start with BE?

Whatever you are practicing right now, you can always start with BE. The important thing is that you should not use another embouchure method. Especially when you start BE. It can cause confusion and may lead to failure. If your fundaments are strong you can always try and experiment with someother methods and try to mix them (I think TCE or Caruso are the only methods that combine with BE). Do not confuse yourself by doing too much at a time. Arban is not an embouchure method, but a great book with a lot of useful studies, but methods like Caruso, TCE, Stamp, Gordon, Spaulding, Thompsons Buzzing book, Lamart's, are not so great to do next to BE if you are not experienced in BE. On the other hand it is very important to play other studies and music next to BE. Every study, concert piece play-along or whatever, is great and probably will sound better after a while.