Some advice needed

I am a 28, nearly 29 year old woman and I have just started trying for a baby with my Partner but I have a nagging doubt that I have fertility issues. I can't explain why I feel like this but I have for years. I have had accidents in the past with ex partners and never conceived and then one ex went on to have a baby with his next girlfriend shortly after we broke up. My query is how soon should you get fertility tested? Is there a set amount of time that you must have been trying before anyone will take you seriously enough to refer you on?