Personally from what I've heard around me the leap between (I)GCSE Languages and A-Level Languages is absolutely huge, but don't let this discourage you. The fact that you really intend to pursue it further into the higher stages of education clearly says something about your interest in these subjects. Two languages is indeed quite a lot, however.
I think Languages are considered facilitating subjects, meaning that they demonstrate strong and balanced skills which is what universities favour, so taking languages definitely won't hamper your chances of getting in (neither would any subject in general). Other facilitating subjects include Mathematics, English Literature, History, Geography, Biology, Chemistry, Physics...
To summarise, the only caveat is the gap between GCSE and A-Level, but a few things can help bridge this potential gap:
- I'm sure some apps or online (free!) services can help. You probably heard of Duolingo; I've used for a brief moment of time before. Not sure how well it really works for learning languages beyond a proficient level though (which may be required at A-Level).
- Star engaging in French or German literature. Many people in my year studied actual French/German texts for their A-Levels (which evidences the big gap between GCSEs and A-Levels)! Watching movies of French/German-related stuff also might help - honestly, this doesn't sound productive but I think it helps to illuminate what you will be studying at A-Level.
- I think you might have to study French/German history as well (so it's not just about grammar as in the case of GCSEs...I think). It's worth doing something on that too.
What do you think your third (or even fourth?) subject might be? And what plans do you have for university? I think Languages (needless to say) and even Law really favours you having a strong language base. I'm sure any additional subjects will be very complementary as well.
Note: I didn't study a foreign Language - not even at IGCSE level (I did First Language Chinese) - so do make sure you confirm everything with teachers or older students with actual experience.
Hope all this is helpful.