Hmm i think there is a glitch where if u dont give her the things in the right order she wont make the potion. You could try going back to a prev save game before u gave her, her last ingredant. Other than that u could try to talk to her while she is somwhere else, say outside her house or in her basement (yes its locked but ive got in it before)

Otherwise dont worry too much about it, to me 40 hours is nothing, plus its kinda refreshing to start over once u know what ur doing more