All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is not permissible for you to day dream having sexual intercourse with either sexes, men or women, as this is a means which leads to committing illegal sexual intercourse. It is for this reason that the Prophet mentioned that desiring with the heart is among the means leading to Zina (fornication and adultery) as he said: "… and the heart desires and wishes, while the private part ratifies that or denies it." What you heard that it is permissible to daydream about this if it has not really occurred is wrong; for more benefit, please refer to Fatwa 92405. Therefore, we advise you to observe fast, acting upon the advice of the Prophet until Allaah facilitates your marriage.
With regard to marrying someone who is older than you, please refer to Fatwa 84745. If the husband has children from a previous marriage, then this is not religiously an obstacle even if the children live with you in the same house. Hence, you should not refuse this man as a husband just because the society views this as abnormal. If this view is taken into account, many religious benefits will not be achieved.
As regards the parents objecting to this marriage, then this is a considerable objection because it is an obligation to obey the parents within what is permissible and it comes in priority over the woman marrying a specific man. However, some scholars are of the view that it is an obligation to obey the parents is conditioned to them facing real harm as a result of this marriage otherwise it is not an obligation to obey them. For more benefit, please refer to Fatwa 84745.
Allaah Knows best.