I asked my girlfriend to come to my house for a day, and she agreed. I really want to be with her. How do I start with her? Do you want to take a shower together first?

Dude, is this your first time? If it's her first time, you should pay special attention to the cleanliness of the bathtub. This is necessary, and you should be gentle when caressing. After all, without experience, you will be happy. If you don't do well, it will have an impact in the future. You should also take contraceptive measures. In a word, safety comes first.