I can sing (how well I would not care to hazard a guess) two or three songs in Gaelic. I sing them very rarely - literally once every few years, if a particular topic to which they are relevant crops up on the night, or somesuch reason. I don't feel comfortable doing it purely for 'performance' because I lack the knowledge to judge my own performance adequately.

However, as to what a Gaelic speaker may think of your efforts, I offer the following anecdote:

Romansch is the fourth language of Switzerland. It is spoken by a very small number of people in the Grisson area. Like French it has two forms of addressing You - a singular (in French 'tu') form which is used only for close friends of a similar age, close family etc. and a plural (in French 'Vous') which is also used for singular people to whom you have no close relationship such as strangers and older people. When they surveyed the language however they found that in Romansch the equivalent of the 'tu' form was used far far more than it was in French. I once asked someone why he thought this was, and he said, after a short pause for thought: I suppose when that few people speak the language, anyone else who tries to is probably going to be thought of as afriend of yours!