There is no single answer, because it varies by lender. Some funders want to see a couple of years of trading before they will look at a proposal. Others consider newly formed businesses and even start-ups, particularly where the director has relevant experience and the asset is a straightforward one. Every case is assessed individually.
The longer you have been trading, the more evidence a lender has to work with, so the choice of funders and the terms available generally improve with time. Two or three years of filed accounts and clean bank statements opens most doors.
If you are newer than that, other things start carrying the weight: your own background in the trade, the deposit you can contribute, the quality and resale value of the asset, your personal credit profile, and whether you are willing to give a personal guarantee.
A business trading for a short period with adverse credit and no deposit is a difficult case, and we will say so. A business trading for a short period run by someone with a long track record in the sector is a very different proposition. Rather than guessing, tell us where you are and we will tell you honestly what is realistic.