Being unsure is a normal condition, including for people who have been coming for years. There is no point of entry here that requires you to have settled the question first, and nobody will ask you to state a position.
Plan Your VisitA lot of people carry the idea that faith is binary. You either have it or you do not, and showing up while undecided is a kind of trespassing. In practice almost nobody lives in that binary. People believe more on some weeks than others, and the people who look most settled from the outside have usually had long stretches where they were not.
You will not be asked where you stand. There is no card to fill out declaring your beliefs, no conversation at the door about your spiritual status, and no moment in the service where the undecided are addressed separately.
What we try to do instead is teach in a way that does not require you to already agree. That means dealing with the actual objections rather than easy versions of them. Ps. Sam has preached full messages on the problem of evil and suffering, on whether miracles are credible, and on the evidence for the resurrection. Those are not sermons written for people who already believe. They are arguments, and you are welcome to find them unconvincing.
Ps. Sam's own background is IIT, a masters and a PhD from MIT, and years as an entrepreneur before he ever did this. He is not asking you to stop thinking in order to participate. The room can hold a real question without getting nervous.
If you want to sit in the back for a few months while you work it out, that is a completely reasonable way to use this place, and it will not cost you anything.
Quick answers
Will anyone ask me to declare what I believe?
No. There is no point in the service or the process where you are asked to state a position.
Does the teaching address hard questions?
Yes. There have been full messages on suffering, on miracles, and on the evidence for the resurrection.
Can I keep attending while undecided?
Yes, for as long as you want. A lot of people do.