That was probably one of the mistakes I first made when I came out of my teaching degree into a full time position. I had a Year 10 math group that were very tough to deal with... fairly sure that made me change my overall attitude towards things haha. If anything, those tough(er) classes are the ones where you develop the most because you are forced into a position where niceness leads to poor outcomes. I was lucky I quickly fixed it up with the help of a fantastic mentor. Mentoring is so important especially in the first year.
Naturally as a younger teacher, the kids are going to relate to you more. For example, the kids at my last school found out very quickly I was a fan of Fallout and kept asking if i'd add them and play.. asked me about my PC specs etc....... it helps build rapport but establishing the line is very important. You are the adult, you are the role model. They don't know any better, you do.
In all honesty, I think my first school turned me into innocent quiet me to coordinator material me. Schools that are "rough" (and I put quotation marks around it because interpretation is varied) are often the ones you get so much out of (if you teach middle years, even better for development). I have found that experienced teachers get quite comfortable in their VCE routine... can't tell you how many times I saw experienced teachers unwilling to try new teaching strategies/even teach middle years.
Like Lear has said, as a young teacher it often is quite difficult to be taken seriously and I often have to reiterate the fact that i'm the kids' teacher, not their friend. That's not to say you can't support them emotionally etc (as all teachers should), but there is a clear distinction that has to be enforced. In essence, you are there to do the job you are paid to do, and leave. For me personally, I have felt that as a very young teacher (I started teaching at 22, I was the youngest teacher in my entire school) I often haven't been taken seriously by both students and colleagues... it doesn't feel great and really the best way to counteract that is to show your professionalism - contribute to things, help others etc. Can't remember the amount of times i've floated the idea of a leadership position.. and as a 23 year old, the looks I get like "as if". So be prepared for some judgement, but that'll pass with time.
First semester is going to be rough in terms of lesson planning etc - but I assure you that it gets easier over time. Think I was up every night till about midnight doing detailed notes in my first term (then realising that they were a waste of time because you understand teaching is so dynamic that a script will never work - adaptability is key).