Life giving you lemons is pretty much the best thing that can happen.
Typically, a recipe will call for either a lemon or a meyer lemon, and it's important to understand the difference.
Regular lemons are intensely sour and very potent, whereas meyer lemons aren't as acidic, and have a subtly sweet, floral flavor. Also, meyer lemons are more orange in color, and have smoother skin.
Substituting one for the other won't make a recipe taste bad, exactly, it'll just taste different. Better to go with whichever variety is suggested.