People rarely introduce themselves with their full name, just first and sur so I don't think it matters too much how many you have or what they sound like with the first name.
Just keep in mind when filling in government documents, bills, etc, they often only have room for one middle name or even just an initial. So as tough as it may be, the "first" middle name is likely the one to be used the most, and you should put some thought into that. If Andrew is more important to you than Matthew, then the order is just fine.