If you don't trust your agent, you are already at a disadvantage. Buyers need to take the choosing of their agent seriously. After all, this is possibly one of the largest purchases of your life, thus far.
It sounds like you already have some knowledge of the recent sold comparables. Educate yourself (sounds like you've done a pretty good job of that already), milk your agent's knowledge (that's what she's there for) and make an educated offer, based on the knowledge you have.
You should never offer more than a house is worth to you. The more you know about the market, the more likely you are going to be successful in getting the house you want for the price you feel comfortable with. A great agent will make the process as painless as possible. An agent who you already don't trust, not so much. Gain knowledge, gain confidence in your agent (or use another one) and look forward to getting the house you want for a fair price.