There are many old AAMC FL's floating around on the internet that are easy to find. Even though the MCAT has changed, they are still a good representative of what you'll see from the AAMC even now days(current AAMC FL's for the new exam will repeat some of these old AAMC FL passages). Do one of these FL's and see how you do.
If you get something like a 10 overall and are completely lost on how to do tons of the questions, then yeah, that's not a great sign. But if feel like the questions are manageable and you can get through them ok and find you can work through these questions, even if your score is low(something like a 24----keep in mind this is before any studying there are things bound to be tested you dont remember anything about) you likely have the capabilities to get a solid score on the real deal with proper preparation.