Greetings of Peace. This inquiry is certainly not new to our forums, but each time it is made the unique qualities of each person bring to it something different such that it always seems to bear more fruit. There is certainly no harm in revisiting it.
I would like to preface my response by reiterating the fact that I am not a spiritual teacher nor an authority of any kind. If I have anything of value to offer you in your dilemma, it stems from my experience of having once been in your situation as well as conversing with many others who have shared similar experiences.
It is also pertinent to note that the peculiar situation that you find yourself in, presented with the decision to choose tradition or rather a particular tradition amongst many is one of the unique symptoms of the spiritual malaise of our age. It is likewise an expression of the heart's natural inclination to turn toward God when placed within the throes of this malaise ...
In principle it is possible for anyone to follow any tradition. However, the conditions of heredity, disposition, and circumstance eliminate many of these possibilities. In the modern west we are effectively left with three primary options, Christianity, Islam, and Buddhism, each of which is a living vibrant tradition uniquely suited to the conditions of the Kali Yuga as they stem from the most recent revelations, and furthermore each is a religion of conversion. This is not to say that these are the only possibilities, but rather that others are simply more remote. If I was to add one more to this list it would be Sikhism, which is also a religion of conversion, but one to which little consideration is generally given in the west.
To answer your question, yes, your Lutheran upbringing subsists as an aspect of your heredity and will impact your entrance into another church or tradition. Whether this influence is positive or negative will largely be determined by the nature of your experience within the Church and any attitudes that you may have developed toward religion in general and Christianity in particular.
In short, I do not believe that it is possible to fully divest ourselves of our heredity, be it positive or negative. We continue to carry with us the effects of the circumstances into which God has placed us. Does this mean that you will be worse off than the person who was not raised in a tradition? I don't think so, but this consideration is highly dependent upon the individual in question. The exponents of the traditional school generally seem to think that by virtue of being born into the west, we are profoundly impacted by Christianity, even if we do not consciously acknowledge the fact ...
In Islam we have a traditional teaching regarding the primordial covenant or fitrah, which states that on the Day of Reckoning, God gathered together all of the souls that would ever be born upon the face of the earth and proposed to them the question "Am I not your Lord?" to which they replied in unison "Indeed, we have testified." According to this teaching, knowledge of God and the aspiration to return to him are woven into the very fabric of our being such that it is not a question of obtaining the necessary determination or faith but rather of removing the impediments that obscure this innate disposition.
Concerning what you should do, although I am not qualified to give spiritual counsel, I do feel comfortable relating a piece of advice given by a respected Shaykh to someone in your situation. Quite simply it is to petition God for guidance and direction while maintaining a humble attitude of prayerful expectancy. This does not mean that you should expect a profound realization or celestial apparition to guide your way but rather that you should maintain the confidence that God in his wisdom and mercy will enable you to make the best decision for yourself when the time is right.
Greetings of Peace. This blog contains selections from my correspondence and other sources on a variety of subjects related to religion, philosophy, and spirituality. I hope that they may be of benefit to the interested reader. Concerning the title of the blog, read this entry.