It is possible to feel in love or infatuated only after 3 months. At the beginning of any relationship, as both individuals learn about one another, they function in the in love stage.
With time, feelings cool. A lot of what a person experiences is based on chemistry (literally) of oxitocin, dopamine, serotonin, adrenaline rush, etc. That is how humans are wired up biologically. Later on, as the influence of these decreases, couples can decide to base their relationship on mutual goals, traits, likes and dislikes, etc.
"I cannot help how I feel." It may not be an issue that you cannot but rather if you're willing....to do this or that. Your emotions also depend on your thoughts (what you think about, what you tell yourself and whether or not you believe it)
Exercising some caution as you're learning about your partner is wise. There is no need to rush into anything. Just make sure that you do not sabotage this opportunity because the past still has a hold on you.