Can I ask if you have any knowledge of schools that specifically don't take ASL as a Foreign Language? My DD is in 8th grade and works as a peer with a deaf student and she will be taking ASL next year at the HS. I have called a few Colleges that she might consider and all have said they accept ASL.
I can answer that at my dd's university (a high ranking private liberal arts school) ASL is not considered a foreign language that can go toward college graduation. Her school requires a minimum 3 class series in a foreign language. My dd studied French in high school and took the mandatory placement exam...she scored high enough to be exempt from the 3 class series, although she has gone ahead and taken 2 add'l upper level French classes to round out her credits.
ASL on high school transcripts may qualify for admission, but if the university requires foreign language to graduate, she may want to have a backround in another language (easier to learn some of the basics at the slower pace in high school). OTOH, there may some larger universities out there that have ASL, so check the graduation requirements of the schools she is interested in.