Will I be able to enter hypnosis?
Nearly everyone can enter the hypnotic state. Interestingly, the actual depth of hypnosis is irrelevant to a successful outcome. It is usually the more intelligent individual with a high motivation for change who achieves the best results.
Can I be made to do anything?
In extreme situations - possibly, but they are very extreme. For example, think of the hypnotic effect the North Korean Leader has over the whole population. They presumably would die for him right now, but if the hypnotic spell was broken - as it was with Romanian Dictator Ceaucescu - he could be shot within a few days by the very people who would have died for him weeks earlier!
In fact the skill of the hypnotherapist is not to reactivate the critical faculty. This would easily occur by the therapist saying something odd or contentious. As a protective measure it's ready to 'resist' at a moments notice.
Do I have to relinquish control?
The hypnotherapist isn't in control of you. The therapist and client form a team. if the client is unwilling to co-operate it is very difficult for the therapist to effect a change. The therapist is just a facilitator. No one can 'put' you there. The challenge is for you to make it happen. It's a skill. Sometimes you'll choose to go and sometimes you wont. It really is up to you.