I was a second year teacher at the head of a high school band program after one year as the JH assistant and not even taking a band to UIL. That year we got a 1-1-2 in marching and a 1-2-2 on stage and sight reading. The "1" on stage was from a hugely successful high school band director who went on to become a FA director in the metroplex. But to contrast the success (in my book) of that first year of me being HS head, the following year we got a 1-2-3 in marching and a "consultant" was hired to help the band program. I was fortunate that my district paid someone $65k/year for three years to help teach me to be a high school band director.
Several years after the fact we're still continuing the success that was started years ago after I had crashed and burned my 2nd year as the HS director.
I don't tell you this to brag. I was an idiot my first two years as a HS director and did things I shouldn't have done. But that's in hindsight. I tell you that to tell you that while it is not 100% guaranteed to fail if you're a VERY young director and the head of the program, the experience and wisdom of working for someone for 3-5 years prior to accepting the head gig anywhere at any level is invaluable. As posted below don't bite off more than you can chew. Find a mentor, preferably someone in your district who you work with, and talk with them daily.
The first year of the consultant being there, as head honcho, was the hardest of my life. To the point that I almost quit the profession. I am thankful every day that between my wife and my faith I was able to make it through working for him for a year. But looking back on it it was an opportunity that I was afforded by my local school board that I don't think I would have been able to have anywhere else. It caused me to become a better teacher and director. Were it not for him I would not be the teacher I feel I am today.