Yes. ASL is a language. I do get your point about the lingual. This has been hotly debated in the past so I hope this thread doesn't erupt into that again.
For you, English, Spanish, and ASL make you trilingual. I have been claiming I am working towards being trilingual myself -- English, ASL and Swedish. I have yet to become even close to being fluent in Swedish, so at the moment I'm still bilingual, IMO.