My children are trilingual. Me, English, dh French and half their schooling is in German (with French).
Supposedly, according to linguistics, a child needs exposure to another language at least 20% of their waking hours to pick it up. This is active, not passive interaction so while videos, etc. help, it doesn't strictly count towards that magic 20%.
To learn a language, small babies and toddlers don't do well in a former learning setting. The language has to have it's own little "kingdom", mom, dad, babysitter, grandparents (if they see them a lot), preschool, etc. You have established your relationship in English so if you start spouting German, don't be surprised to get a lukewarm, if not outright cold reception from your little one.
Just to clear up two misconceptions you had in your original post. 1. Both parents do NOT have to speak the language. I don't speak German and my dh can't speak English but our children speak both. It's also way less awkward than you'd think. We rarely have to translate for him and he now understands English very well.
Also, a child can learn a language with an accent and speak it later without as long as at some point, he or she is exposed to the "real" version. Example, a parent speaks to the child with an accent, later attends a school where it it taught and then the child will speak like the teacher, not the parent. Same goes if the child travels to that country, or is in contact with native speakers on a regular basis.
Now the good news; the better the child picks up the second language, the easier the third comes. I know from experience! My kids had an easier time just because their brain was already wired in two languages. So unless you have a German preschool or German speaking daycare provider, it would be a better effort to concentrate on getting the Portuguese well established, so that she's prepped to learn German or whatever language later on.
Got to run!