I would have to agree with the majority, get yourself a nice walk behind mower and look into a hydro mower.
myself for example, this is also our first season. in March we started with a pick up truck, 2 push mowers, 2 shindaiwa weed wackers and a residential echo back pack blower with 6 accounts.
with some advertising, word of mouth, friends/family we grew to 30 accounts!!
we purchased a 12 foot trailer, a red max back pack blower, 52 inch hydro walk behind all from criagslist. during the summer we found a 48 hydro mower on craigslist for a great price and purchased that.
we bought a 8hp push blower (on craigslist)
and recently we grew out of the 12 foot trailer, we purchased a 16 foot trailer with basket, trimmer rack and blower racks...a kawasaki weed wacker and Shindaiwa backpack blower.
we are not huge or even big, but we are manageable for 2 people. this next season I would like to sell the 52 inch hydro and possibly finance a exmark turf tracer.
keep it simple, do great work and try not to get too big too fast. keep it manageable