Get two people onto the team immediately so that you have a scapegoat available for when things inevitably go wrong.
Seriously, though, communication is the key. Build out the most detailed to-do lists you can for yourself and potential team members, and don't forget to budget for boring things like documentation, code commentary, testing and so on, Pad your time estimates for each part by a factor of two (or more) to reflect your inexperience and uncertainty - never ever ever fall into the trap of thinking 'this'll be quick and easy', that's often a sign that you haven't fully thought through the problem. Also have a strong backup strategy for situations where you put code into production and it fails, especially the circumstances where it works fora while and then falls over - you don't want to be trying to decide to between whether to revert the code base or lose critical business data.
Then make a shorter summary version and discuss that with your employer. Be frank with him about both your excitement but also your worries, and try to figure out a protocol between you about what to do when there are problems. Ask him about problems he's had in the past with other people and what did or didn't work. Also agree something about working standards and so on so that you don't put yourself into a burnout situation, which is a particular problem if you're the new hotness.
Lastly, really really work on your people skills. Take time to understand other people's needs in different departments, and when you want to innovate ask how best you can support them through that change, and again what good or bad experiences they may have had in the past. If you're young, this is a great opportunity to give up Bullshit - the impulse to always give an answer, even if you are making it up as you go. Even though you'll often be right, and though it might be sincerely intended as a good answer, the tendency to produce a novel answer on the spot is very seductive because it makes you look and feel clever - but if it turns out to be incorrect then you are in a real bind, and have to either deal with shame for admitting you messed up or try to cover your tracks, which often makes things worse (see the world of politics for innumerable examples from all politicians).
When you step into a position of responsibility - and this is not just true in the workplace but in your personal and civic life - one of your most valuable assets is the ability to say 'I don't know' and then deal with that reality. At first you'll get some pushback from people - clients, colleagues, whoever - who'll question your abilities or skillset, but it's always better to acknowledge uncertainty and deal with it than to bluff your way through. People are superficially impressed by bullshit artists but once the inevitable letdowns occur, they really really hate the feeling of having been lied to, and eventually that toxicity is a killer. The joke I made at the beginning of this post is the bullshit artist's default mode of operation. Stay off that path, work hard, and things will be fine.