Hi Patty,
Welcome to VAF. This is truly a great forum for VAs.
There really is no magic bullet to get 25 posts other than to participate in posts. When I first logged onto VAF, I started checking out those thread topics which were of interest to me. I had questions about billing and client relations so I popped over to those sections and simply got involved reading and asking questions of other people's posts. I even did a search and then found out that no one had asked a particular question so I started my own thread. As folks started to answer me, I answered back and before you know it I had half my posts.
Another way to gain 25 posts is to offer information to other VAs. Think of it as engaging in a conversation. For example, today I was reading Social Media Examiner and came upon an article about
5 Social Media Mistakes that Hurt Your Sales This might make a nice topic for conversation; allow me to make comments so others can get to know me and add value to the forum for others to use.
Before you know it...you will be up to 25 posts.

Plus, it is great way to gain exposure. All threads are indexed by the search engines with the exception of the members-only sections.
Janine