welcome to "theravada",
I consider myself an agnostic, always have, I've never felt anything in the theravada or pali scriptures was so mythical or fantastic that it took away from the important part, the practice here and now. Even the Buddha himself really spoke more about practice, practice, practice, look at his last words.
for those who really get hung up on rebirth and kamma I always offer the Kalama sutta, not the famous paragraph, but one down at the bottomhttp://www.accesstoinsight.org/tipitaka ... .than.html"Now, Kalamas, one who is a disciple of the noble ones — his mind thus free from hostility, free from ill will, undefiled, & pure — acquires four assurances in the here-&-now:
"'If there is a world after death, if there is the fruit of actions rightly & wrongly done, then this is the basis by which, with the break-up of the body, after death, I will reappear in a good destination, the heavenly world.' This is the first assurance he acquires.
"'But if there is no world after death, if there is no fruit of actions rightly & wrongly done, then here in the present life I look after myself with ease — free from hostility, free from ill will, free from trouble.' This is the second assurance he acquires."
You never hear the Buddha say " hah you don't believe in rebirth? you suck then you can't be a buddhist"... instead he takes a pragmatic approach.. even if there is no such thing as rebirth and kamma.. you live skillfully and in peace right here and now, how can you go wrong?