What is the best solution for my case?
Well, the answer is: it depends on you! What is your preferred learning style? Are you timid? Are you an extrovert person?
Extrovert people tend to learn Portuguese faster then timid and introvert Portuguese students.
If you believe that you will need a bit more time than the average, you should pick individual lessons because your teacher will follow your rhythm without any pressure.
Learning in a small group of Portuguese students in Lisbon can be challenging as you can feel yourself under pressure (especially if you need a bit more time than the usual to understand the content).
If you are short of money or if you like to socialize, Portuguese group lessons are certainly the best option. In this case, you won’t have a Portuguese teacher always on top of you. But you have to adjust yourself to the needs of the group/class (that be a bit different from your own needs).
Learning Portuguese in a group can also be very funny because of the differences that students have among them. Also because Portuguese students tend to help other students. This attitude creates a bond between Portuguese students that, very often, will be maintained over time. In fact, learning Portuguese in Lisbon can be much more than just learning a new language.
Regardless of your choice, the most important thing is to maintain consistency and focus. Do not forget that learning Portuguese (or another language) is always a marathon (not a speed race).
Another important tip: make sure that your classes are good fun! No one can learn languages with boring lessons! Relax and have fun! If your Portuguese classes (individual or group) are boring you have a simple solution: try another teacher or another school!
You must feel a sense of well-being and fun when you’re getting to your Portuguese lessons!