How was my performance in the Fifth precept

How bad is that?

I think the full text of the "fifth precept" is translated more-or-less like this:

I undertake the precept to refrain from intoxicating drinks and drugs which lead to carelessness.

It's also translated as negligence or heedlessness -- see Pamāda:

negligence; indolence; remissness; carelessness

So I think what you said is an example: i.e. "I forgot (about my Buddha statue)" seems like an example of the "carelessness" or "heedlessness" which the precept warns against.

And that's a condition for "unskillful behaviour".

And that in turn is a condition for "remorse".

Am I a bad person for that mistake?

Yes and no, in my opinion.

I learned a little of the training given to pre-school teachers -- and part of that is that you do not say to children, "You're a bad person" -- instead you'd say, "That's bad behaviour", and model (i.e. provide examples of) better behaviour.

So I'd say that it's "unskillful behaviour", and hope that you learn to avoid it, and realise the benefits of avoiding it -- find that you're happier when you don't do things you regret -- even lasting happiness:

So the absence of remorse is conditioned, but not being an existing thing, not having been constructed (sankharaed)-- it was the result of not-doing, is not itself subject to ending and is a small taste of Nibbana. Remorse being relative to its cause and the cause being removed the remorse is removed forever. Remorse may return but it will be based on another ill-conceived act.

I’m going to not take any more marijuana until ...

My "refraining" seems to be permanent. I rarely have the opportunity to take it, I don't meet with people like that -- and when I do have the opportunity I don't take it, because I fear that I'd regret it after I have done it. I know that there are short-term disadvantages (e.g. "disability" as well as "pleasure"), and long-term also (mainly attaching to the habit and feeding the craving, but also spending time and money and health and maybe developing unhealthy social relationships, instead of whatever else you might be doing or not doing).

It's just easier not to start, never to start.

Once you've trained yourself to have the habit, it's also possible to untrain yourself, to learn how to stop and why.

1. You are very bad before you started Buddhism because you never feel sorry for taking marijuana and never try to stop.

2. You have forgotten Buddha statue for entire life and through many lives before until now you are trying to remember your Buddha statue.

You before now or now who you being are worse?

Practices are very long for uncountable lives because it is very hard beyond expectation of the ordinary.

So, what you can do now is reciting percepts again and again until you getting Attained-Jhana which is better than marijuana uncountable time.

We feel happy to understand the cons of taking marijuana, but we are not stress, worry, and sad of what we did because no one can retake anything in the past. Reciting precepts again and again with happiness is what we can do now actually. Move on! You have tried and trying, this is the best we can do now "remaking the resolution again and again".

Buddhism doesn't really have a concept of 'bad person' because the aim in buddhism is to release both identity associations and the egoic mind that clings to them. The problem here is that you did something you had decided you weren't going to do. It was a lapse, not an act of disrespect; have compassion for yourself and for the tangle you've snared yourself in. Then just be aware:

• Be aware of what you did
• Be aware of what you might do
• Be aware of what you're doing

That's the middle path.