Sweet summer child
You need more than posts… 
To fet to trust level 3 You:
- Must have visited at least 50% of last 100 days
- Must have replied to at least 10 different topics
- Of topics created in the last 100 days, must have viewed 500 topics
- Of posts created in the last 100 days, must have read 20,000 posts (both starting posts and replies)
- Must have received 20 likes, and given 30 likes.
- Must not have received more than 5 spam or offensive flags (with unique posts and unique users for each, confirmed by a moderator)
- Must not have been suspended (including forum suspensions or in-game account actions of any Blizzard game)