I'm a language teacher, and I can tell you your Spanish is fluid and the pronunciation is good enough so everything is understood (which is the most important thing). You do have a strong American accent, but we all have accents. As long as it's understandable, accent is not a problem (think of Arnold Swarzenegger speanking English: he sounds super Austrian, but still you understand everything he sais, and he's lived and worked in the US without problems).
About your doubt whether having learned Mexican Spanish affects your communication with speakers of European Spanish: not at all. I'm from Spain and learned English in the UK, but when I lived in NYC I had zero communication problems. That would be you in Spain, Equatorial Guinea, Argentina or any Spanish speaking country.
The difference between dialects of Spanish is more or less like the one between dialects of English. So if u put together four people (one from Mexico, one from Chile, one from Spain and one from Equatorial Guinea), they will speak with zero communication problems (despite different accents and a couple of words they may use). It would be exactly like one American, one British, one Australian and one South African: they will understand everything without problems.
