I agree with much of what is said above by the other members.
My girlfriend and I went through a rough period recently, and, for the most part, things are much better now.
In your case, it seems, based on your previous threads as well, that Jennifer isn't ready to commit to either a relationship or marriage, at this point that is.
Ultimately only you (and Jennifer, of course) can decide what is the right decision for (both of) you
, but I would listen to, not necessarily act on, the advice being given.
This will at least give you another (external) perspective, which might open your eyes to things you hadn't thought of or seen in your relationship.
Always (while you are together I mean) keep the lines of communication between the two of you active!
Relationships are often tricky, but if they are meant to be, one will usually find out in due time.
No matter what happens, I wish you both the best of luck!