As has been indicated, VAT is irrelevant with regard to whether you decide to set up a limited company or not. Your turnover is well below the threshold, so neither you(as a sole trader) or your limited company can become a 'taxable person' for VAT purposes [unless you do so voluntarily].
(The term 'taxable person' applies to anyone who pays VAT, irrespective of whether the 'person' is an individual, a club, a charity or a business employing tens of thousands of people).
There have been several studies that show that consumers are more likely to put their trust in a business that has 'Ltd' on the end of the name, rather than in a sole trader. (Which is actually rather odd because, if a sole trader's business fails, customers can sue the boss personally but they can't sue the directors or shareholders of a limited company. It seems that, for some strange reason, 'Ltd' is seen as indicating 'professionalism').
If there's a chance that the failure of your business could put your major personal assets (such as your home) at risk then you DEFINITELY need to set up a limited company (to divorce your assets from those of the business). Otherwise there might be little point in doing so at the present time unless you think that having 'Ltd' on the end of the company name would make your business look more professional.