mai-ling is right. Starting with Spanish will be easiest for most people (native English speakers anyway). The key is finding a good program that offers audio lessons so you can be sure that you pronunciation is correct.

I’m using Rocket Spanish right now (I just started) as it was recommended by one of my friends; a teacher actually. It’s a nice program and came with free trial lessons. Good luck!

For an English native speaker, Spanish is usually quite easy, but German is aweful. Especially the German grammar is horrible. But perhaps it is more of an advantage to learn something difficult? When you learn first Spanish and then German or the other way around, I don´t think the first language will be a great help when learning the other one.

german isnt easy to learn
some english native speakers, espcecially US americans who learned german for 4 years think they speak good german but in fact their german is very very bad and wrong

donnu about spanish

You can learn both without difficulty and should be able to speak both fluently with practice and a lot of interaction with Spanish and German speaking peoples.
I’ve taken classes in both languages and even as dumb as I am I felt that I could have learned to speak both fluently if I had kept with it.

I´m Spanish and I don´t know which one would be more difficult for an English-speaker, I guess German is closer to English. Although, Spanish is much more widely spoken.