Mentally, an appropriate tool would be to see the mentalities of the ones that you know and they can do or did your self-defense goals, several times with ease. If they are nice, accurate and honest, they will be able to aid you or give you something on that.

20 years old is not old at all.

For more physical strength you can do weights training. You can go to a gym and find a fitness instructor. He/she will be able to help you with that.

For adding more weight in muscles, you can combine your weights training, with more food rich in proteins, but don't forget to balance it with food rich in vitamins and carbohydrates.

Splits are not necessary and high or jumping kicks are not a tool that people use that often in self-defense.

You can see improvements, both in the first day and after 20-30-40 years as well.

For martial arts you have an instructor.:)

Good luck:)

if 3, 4 or 5 guys come at you and you can run like a scared rabbit then that is precisely what you should do. Standing there when you can flee is egotistical rubbish that is likely to get you killed.

No 20 years of age is not too old, lots of people start at this age and many start much older.

Downloading things from the internet without a coach to help you correct the procedure will not work. You should stick to your training that you have started and there is nothing anyone else can do to motivate you, simply because if you are not motivated then that is your issue no one elses.

You journey through martial arts will never stop the learning and improvement, this is why we train our entire life.

I think you need a good talk with your Aiki teacher to dispel some or your misconceptions of martial arts.

motivation