Be prepared just in case either way, it is not uncommon for a partner to be completely accepting of others but controlling and hostile if it is their own child.

By prepared I mean in worst case scenario:

1. Where can you sleep that night and who are your allies.
2. Where will you go.
3. Will you be working or going to school.
4. If school, what kind of scholarships and savings do you have (and are those saving accessible to you without parental consent).

It is sad that these even need to be considered, but I know people who have had to use these steps and it is better to think them out in advance.

In my experience, people who are opposed to LGBTQ lifestyles are usually pretty vocal about it without being asked.

You could bring up a news story about an LGTBQ celebrity and gauge their reaction.