Is Mexico a Third world country?

I visited a city in Mexico I think it's called Jalisco and I though that it was gonna look like a third world country but when I got there it was very nice and stuff, and the taxis where even luxurious they where Escalades SUVs. I don't get it because I been in Tijuana which is another city from Mexico and it looks Very poor, houses built in the mountains and stuff,but that's not the case in Jalisco houses are nice there why is that? Is it the corruption?