Definitely get yourself ready for language boot-camp- it's not impossible but it can be a little overwhelming at first. I think it might be actually a bit easier for you having a prior knowledge of the language that's spoken in your country of service- at least you won't feel as lost the first couple of weeks. When I came to Kyrgyzstan I knew no Kyrgyz and no Russian and the first couple of days were challenging. We all live with host families here and it's kind of like you just have to start speaking the language or your screwed.

Judging by what most have been posting here, it sounds like our PST may have been a little different- the two main languages here are Kyrgyz and Russian (in my opinion you kind of have to know both- one really well and a little bit of the other), so our group was split between Russian learners and Kyrgyz learners- the Russian group being the minority language. Our sessions were between five to six hours Monday through Saturday which I know sounds kind of brutal but once you get the hang of it, it's not so bad. The first couple of sessions are exhausting and by the end of the day you feel like you really can't jam any more information in your brain but you'll adjust. Your LCFs (Language and Cultural Facilitators) will be great teachers- games, conversation activities, lots of flip-chart stuff, etc. My advice is just try to find your zen-place before the first couple of sessions because it will be intensive in every sense of the word.

At the end of PST, I tested Intermediate High in Kyrgyz having had no prior knowledge of the language. Most people in my group ranged from Intermediate low to high. Just try to budget at least an hour each day to study on your own outside of language sessions and make an effort to practice with your teachers and locals as much as possible. Good luck!!